Text file src/cmd/compile/internal/ssa/_gen/generic.rules

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Simplifications that apply to all backend architectures. As an example, this
     6  // Go source code
     7  //
     8  // y := 0 * x
     9  //
    10  // can be translated into y := 0 without losing any information, which saves a
    11  // pointless multiplication instruction. Other .rules files in this directory
    12  // (for example AMD64.rules) contain rules specific to the architecture in the
    13  // filename. The rules here apply to every architecture.
    14  //
    15  // The code for parsing this file lives in rulegen.go; this file generates
    16  // ssa/rewritegeneric.go.
    17  
    18  // values are specified using the following format:
    19  // (op <type> [auxint] {aux} arg0 arg1 ...)
    20  // the type, aux, and auxint fields are optional
    21  // on the matching side
    22  //  - the type, aux, and auxint fields must match if they are specified.
    23  //  - the first occurrence of a variable defines that variable.  Subsequent
    24  //    uses must match (be == to) the first use.
    25  //  - v is defined to be the value matched.
    26  //  - an additional conditional can be provided after the match pattern with "&&".
    27  // on the generated side
    28  //  - the type of the top-level expression is the same as the one on the left-hand side.
    29  //  - the type of any subexpressions must be specified explicitly (or
    30  //    be specified in the op's type field).
    31  //  - auxint will be 0 if not specified.
    32  //  - aux will be nil if not specified.
    33  
    34  // blocks are specified using the following format:
    35  // (kind controlvalue succ0 succ1 ...)
    36  // controlvalue must be "nil" or a value expression
    37  // succ* fields must be variables
    38  // For now, the generated successors must be a permutation of the matched successors.
    39  
    40  // constant folding
    41  (Trunc16to8  (Const16  [c])) => (Const8   [int8(c)])
    42  (Trunc32to8  (Const32  [c])) => (Const8   [int8(c)])
    43  (Trunc32to16 (Const32  [c])) => (Const16  [int16(c)])
    44  (Trunc64to8  (Const64  [c])) => (Const8   [int8(c)])
    45  (Trunc64to16 (Const64  [c])) => (Const16  [int16(c)])
    46  (Trunc64to32 (Const64  [c])) => (Const32  [int32(c)])
    47  (Cvt64Fto32F (Const64F [c])) => (Const32F [float32(c)])
    48  (Cvt32Fto64F (Const32F [c])) => (Const64F [float64(c)])
    49  (Cvt32to32F  (Const32  [c])) => (Const32F [float32(c)])
    50  (Cvt32to64F  (Const32  [c])) => (Const64F [float64(c)])
    51  (Cvt64to32F  (Const64  [c])) => (Const32F [float32(c)])
    52  (Cvt64to64F  (Const64  [c])) => (Const64F [float64(c)])
    53  (Cvt32Fto32  (Const32F [c])) && c >= -1<<31 && c < 1<<31 => (Const32 [int32(c)])
    54  (Cvt32Fto64  (Const32F [c])) && c >= -1<<63 && c < 1<<63 => (Const64 [int64(c)])
    55  (Cvt64Fto32  (Const64F [c])) && c >= -1<<31 && c < 1<<31 => (Const32 [int32(c)])
    56  (Cvt64Fto64  (Const64F [c])) && c >= -1<<63 && c < 1<<63 => (Const64 [int64(c)])
    57  (Round32F x:(Const32F)) => x
    58  (Round64F x:(Const64F)) => x
    59  (CvtBoolToUint8 (ConstBool [false])) => (Const8 [0])
    60  (CvtBoolToUint8 (ConstBool [true])) => (Const8 [1])
    61  (BitLen64 (Const64 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.Len64(uint64(c)))])
    62  (BitLen32 (Const32 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.Len32(uint32(c)))])
    63  (BitLen16 (Const16 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.Len16(uint16(c)))])
    64  (BitLen8  (Const8  [c])) && config.PtrSize == 8 => (Const64 [int64(bits.Len8(uint8(c)))])
    65  (BitLen64 (Const64 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.Len64(uint64(c)))])
    66  (BitLen32 (Const32 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.Len32(uint32(c)))])
    67  (BitLen16 (Const16 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.Len16(uint16(c)))])
    68  (BitLen8  (Const8  [c])) && config.PtrSize == 4 => (Const32 [int32(bits.Len8(uint8(c)))])
    69  (PopCount64 (Const64 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.OnesCount64(uint64(c)))])
    70  (PopCount32 (Const32 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.OnesCount32(uint32(c)))])
    71  (PopCount16 (Const16 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.OnesCount16(uint16(c)))])
    72  (PopCount8  (Const8  [c])) && config.PtrSize == 8 => (Const64 [int64(bits.OnesCount8(uint8(c)))])
    73  (PopCount64 (Const64 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.OnesCount64(uint64(c)))])
    74  (PopCount32 (Const32 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.OnesCount32(uint32(c)))])
    75  (PopCount16 (Const16 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.OnesCount16(uint16(c)))])
    76  (PopCount8  (Const8  [c])) && config.PtrSize == 4 => (Const32 [int32(bits.OnesCount8(uint8(c)))])
    77  (Add64carry (Const64 <t> [x]) (Const64 [y]) (Const64 [c])) && c >= 0 && c <= 1 => (MakeTuple (Const64 <t> [bitsAdd64(x, y, c).sum]) (Const64 <t> [bitsAdd64(x, y, c).carry]))
    78  
    79  (Trunc16to8  (ZeroExt8to16  x)) => x
    80  (Trunc32to8  (ZeroExt8to32  x)) => x
    81  (Trunc32to16 (ZeroExt8to32  x)) => (ZeroExt8to16  x)
    82  (Trunc32to16 (ZeroExt16to32 x)) => x
    83  (Trunc64to8  (ZeroExt8to64  x)) => x
    84  (Trunc64to16 (ZeroExt8to64  x)) => (ZeroExt8to16  x)
    85  (Trunc64to16 (ZeroExt16to64 x)) => x
    86  (Trunc64to32 (ZeroExt8to64  x)) => (ZeroExt8to32  x)
    87  (Trunc64to32 (ZeroExt16to64 x)) => (ZeroExt16to32 x)
    88  (Trunc64to32 (ZeroExt32to64 x)) => x
    89  (Trunc16to8  (SignExt8to16  x)) => x
    90  (Trunc32to8  (SignExt8to32  x)) => x
    91  (Trunc32to16 (SignExt8to32  x)) => (SignExt8to16  x)
    92  (Trunc32to16 (SignExt16to32 x)) => x
    93  (Trunc64to8  (SignExt8to64  x)) => x
    94  (Trunc64to16 (SignExt8to64  x)) => (SignExt8to16  x)
    95  (Trunc64to16 (SignExt16to64 x)) => x
    96  (Trunc64to32 (SignExt8to64  x)) => (SignExt8to32  x)
    97  (Trunc64to32 (SignExt16to64 x)) => (SignExt16to32 x)
    98  (Trunc64to32 (SignExt32to64 x)) => x
    99  
   100  (ZeroExt8to16  (Const8  [c])) => (Const16 [int16( uint8(c))])
   101  (ZeroExt8to32  (Const8  [c])) => (Const32 [int32( uint8(c))])
   102  (ZeroExt8to64  (Const8  [c])) => (Const64 [int64( uint8(c))])
   103  (ZeroExt16to32 (Const16 [c])) => (Const32 [int32(uint16(c))])
   104  (ZeroExt16to64 (Const16 [c])) => (Const64 [int64(uint16(c))])
   105  (ZeroExt32to64 (Const32 [c])) => (Const64 [int64(uint32(c))])
   106  (SignExt8to16  (Const8  [c])) => (Const16 [int16(c)])
   107  (SignExt8to32  (Const8  [c])) => (Const32 [int32(c)])
   108  (SignExt8to64  (Const8  [c])) => (Const64 [int64(c)])
   109  (SignExt16to32 (Const16 [c])) => (Const32 [int32(c)])
   110  (SignExt16to64 (Const16 [c])) => (Const64 [int64(c)])
   111  (SignExt32to64 (Const32 [c])) => (Const64 [int64(c)])
   112  
   113  (Neg8   (Const8   [c])) => (Const8   [-c])
   114  (Neg16  (Const16  [c])) => (Const16  [-c])
   115  (Neg32  (Const32  [c])) => (Const32  [-c])
   116  (Neg64  (Const64  [c])) => (Const64  [-c])
   117  (Neg32F (Const32F [c])) && c != 0 => (Const32F [-c])
   118  (Neg64F (Const64F [c])) && c != 0 => (Const64F [-c])
   119  
   120  (Add8   (Const8 [c])   (Const8 [d]))   => (Const8  [c+d])
   121  (Add16  (Const16 [c])  (Const16 [d]))  => (Const16 [c+d])
   122  (Add32  (Const32 [c])  (Const32 [d]))  => (Const32 [c+d])
   123  (Add64  (Const64 [c])  (Const64 [d]))  => (Const64 [c+d])
   124  (Add32F (Const32F [c]) (Const32F [d])) && c+d == c+d => (Const32F [c+d])
   125  (Add64F (Const64F [c]) (Const64F [d])) && c+d == c+d => (Const64F [c+d])
   126  (AddPtr <t> x (Const64 [c])) => (OffPtr <t> x [c])
   127  (AddPtr <t> x (Const32 [c])) => (OffPtr <t> x [int64(c)])
   128  
   129  (Sub8   (Const8 [c]) (Const8 [d]))     => (Const8 [c-d])
   130  (Sub16  (Const16 [c]) (Const16 [d]))   => (Const16 [c-d])
   131  (Sub32  (Const32 [c]) (Const32 [d]))   => (Const32 [c-d])
   132  (Sub64  (Const64 [c]) (Const64 [d]))   => (Const64 [c-d])
   133  (Sub32F (Const32F [c]) (Const32F [d])) && c-d == c-d => (Const32F [c-d])
   134  (Sub64F (Const64F [c]) (Const64F [d])) && c-d == c-d => (Const64F [c-d])
   135  
   136  (Mul8   (Const8 [c])   (Const8 [d]))   => (Const8  [c*d])
   137  (Mul16  (Const16 [c])  (Const16 [d]))  => (Const16 [c*d])
   138  (Mul32  (Const32 [c])  (Const32 [d]))  => (Const32 [c*d])
   139  (Mul64  (Const64 [c])  (Const64 [d]))  => (Const64 [c*d])
   140  (Mul32F (Const32F [c]) (Const32F [d])) && c*d == c*d => (Const32F [c*d])
   141  (Mul64F (Const64F [c]) (Const64F [d])) && c*d == c*d => (Const64F [c*d])
   142  (Mul32uhilo (Const32 [c]) (Const32 [d])) => (MakeTuple (Const32 <typ.UInt32> [bitsMulU32(c, d).hi]) (Const32 <typ.UInt32> [bitsMulU32(c,d).lo]))
   143  (Mul64uhilo (Const64 [c]) (Const64 [d])) => (MakeTuple (Const64 <typ.UInt64> [bitsMulU64(c, d).hi]) (Const64 <typ.UInt64> [bitsMulU64(c,d).lo]))
   144  (Mul32uover (Const32 [c]) (Const32 [d])) => (MakeTuple (Const32 <typ.UInt32> [bitsMulU32(c, d).lo]) (ConstBool <typ.Bool> [bitsMulU32(c,d).hi != 0]))
   145  (Mul64uover (Const64 [c]) (Const64 [d])) => (MakeTuple (Const64 <typ.UInt64> [bitsMulU64(c, d).lo]) (ConstBool <typ.Bool> [bitsMulU64(c,d).hi != 0]))
   146  
   147  (And8   (Const8 [c])   (Const8 [d]))   => (Const8  [c&d])
   148  (And16  (Const16 [c])  (Const16 [d]))  => (Const16 [c&d])
   149  (And32  (Const32 [c])  (Const32 [d]))  => (Const32 [c&d])
   150  (And64  (Const64 [c])  (Const64 [d]))  => (Const64 [c&d])
   151  
   152  (Or8   (Const8 [c])   (Const8 [d]))   => (Const8  [c|d])
   153  (Or16  (Const16 [c])  (Const16 [d]))  => (Const16 [c|d])
   154  (Or32  (Const32 [c])  (Const32 [d]))  => (Const32 [c|d])
   155  (Or64  (Const64 [c])  (Const64 [d]))  => (Const64 [c|d])
   156  
   157  (Xor8   (Const8 [c])   (Const8 [d]))   => (Const8  [c^d])
   158  (Xor16  (Const16 [c])  (Const16 [d]))  => (Const16 [c^d])
   159  (Xor32  (Const32 [c])  (Const32 [d]))  => (Const32 [c^d])
   160  (Xor64  (Const64 [c])  (Const64 [d]))  => (Const64 [c^d])
   161  
   162  (Ctz64 (Const64 [c])) && config.PtrSize == 4 => (Const32 [int32(ntz64(c))])
   163  (Ctz32 (Const32 [c])) && config.PtrSize == 4 => (Const32 [int32(ntz32(c))])
   164  (Ctz16 (Const16 [c])) && config.PtrSize == 4 => (Const32 [int32(ntz16(c))])
   165  (Ctz8  (Const8  [c])) && config.PtrSize == 4 => (Const32 [int32(ntz8(c))])
   166  
   167  (Ctz64 (Const64 [c])) && config.PtrSize == 8 => (Const64 [int64(ntz64(c))])
   168  (Ctz32 (Const32 [c])) && config.PtrSize == 8 => (Const64 [int64(ntz32(c))])
   169  (Ctz16 (Const16 [c])) && config.PtrSize == 8 => (Const64 [int64(ntz16(c))])
   170  (Ctz8  (Const8  [c])) && config.PtrSize == 8 => (Const64 [int64(ntz8(c))])
   171  
   172  (Div8   (Const8  [c])  (Const8  [d])) && d != 0 => (Const8  [c/d])
   173  (Div16  (Const16 [c])  (Const16 [d])) && d != 0 => (Const16 [c/d])
   174  (Div32  (Const32 [c])  (Const32 [d])) && d != 0 => (Const32 [c/d])
   175  (Div64  (Const64 [c])  (Const64 [d])) && d != 0 => (Const64 [c/d])
   176  (Div8u  (Const8  [c])  (Const8  [d])) && d != 0 => (Const8  [int8(uint8(c)/uint8(d))])
   177  (Div16u (Const16 [c])  (Const16 [d])) && d != 0 => (Const16 [int16(uint16(c)/uint16(d))])
   178  (Div32u (Const32 [c])  (Const32 [d])) && d != 0 => (Const32 [int32(uint32(c)/uint32(d))])
   179  (Div64u (Const64 [c])  (Const64 [d])) && d != 0 => (Const64 [int64(uint64(c)/uint64(d))])
   180  (Div32F (Const32F [c]) (Const32F [d])) && c/d == c/d => (Const32F [c/d])
   181  (Div64F (Const64F [c]) (Const64F [d])) && c/d == c/d => (Const64F [c/d])
   182  (Div128u <t> (Const64 [0]) lo y) => (MakeTuple (Div64u <t.FieldType(0)> lo y) (Mod64u <t.FieldType(1)> lo y))
   183  
   184  (Not (ConstBool [c])) => (ConstBool [!c])
   185  
   186  (Floor       (Const64F [c])) => (Const64F [math.Floor(c)])
   187  (Ceil        (Const64F [c])) => (Const64F [math.Ceil(c)])
   188  (Trunc       (Const64F [c])) => (Const64F [math.Trunc(c)])
   189  (RoundToEven (Const64F [c])) => (Const64F [math.RoundToEven(c)])
   190  
   191  // Convert x * 1 to x.
   192  (Mul(8|16|32|64)  (Const(8|16|32|64)  [1]) x) => x
   193  (Mul(32|64)uover <t> (Const(32|64) [1]) x) => (MakeTuple x (ConstBool <t.FieldType(1)> [false]))
   194  
   195  // Convert x * -1 to -x.
   196  (Mul(8|16|32|64)  (Const(8|16|32|64)  [-1]) x) => (Neg(8|16|32|64)  x)
   197  
   198  // DeMorgan's Laws
   199  (And(8|16|32|64) <t> (Com(8|16|32|64) x) (Com(8|16|32|64) y)) => (Com(8|16|32|64) (Or(8|16|32|64) <t> x y))
   200  (Or(8|16|32|64) <t> (Com(8|16|32|64) x) (Com(8|16|32|64) y)) => (Com(8|16|32|64) (And(8|16|32|64) <t> x y))
   201  
   202  // Convert multiplication by a power of two to a shift.
   203  (Mul8  <t> n (Const8  [c])) && isPowerOfTwo(c) => (Lsh8x64  <t> n (Const64 <typ.UInt64> [log8(c)]))
   204  (Mul16 <t> n (Const16 [c])) && isPowerOfTwo(c) => (Lsh16x64 <t> n (Const64 <typ.UInt64> [log16(c)]))
   205  (Mul32 <t> n (Const32 [c])) && isPowerOfTwo(c) => (Lsh32x64 <t> n (Const64 <typ.UInt64> [log32(c)]))
   206  (Mul64 <t> n (Const64 [c])) && isPowerOfTwo(c) => (Lsh64x64 <t> n (Const64 <typ.UInt64> [log64(c)]))
   207  (Mul8  <t> n (Const8  [c])) && t.IsSigned() && isPowerOfTwo(-c) => (Neg8  (Lsh8x64  <t> n (Const64 <typ.UInt64> [log8(-c)])))
   208  (Mul16 <t> n (Const16 [c])) && t.IsSigned() && isPowerOfTwo(-c) => (Neg16 (Lsh16x64 <t> n (Const64 <typ.UInt64> [log16(-c)])))
   209  (Mul32 <t> n (Const32 [c])) && t.IsSigned() && isPowerOfTwo(-c) => (Neg32 (Lsh32x64 <t> n (Const64 <typ.UInt64> [log32(-c)])))
   210  (Mul64 <t> n (Const64 [c])) && t.IsSigned() && isPowerOfTwo(-c) => (Neg64 (Lsh64x64 <t> n (Const64 <typ.UInt64> [log64(-c)])))
   211  
   212  (Mod8  (Const8  [c]) (Const8  [d])) && d != 0 => (Const8  [c % d])
   213  (Mod16 (Const16 [c]) (Const16 [d])) && d != 0 => (Const16 [c % d])
   214  (Mod32 (Const32 [c]) (Const32 [d])) && d != 0 => (Const32 [c % d])
   215  (Mod64 (Const64 [c]) (Const64 [d])) && d != 0 => (Const64 [c % d])
   216  
   217  (Mod8u  (Const8 [c])  (Const8  [d])) && d != 0 => (Const8  [int8(uint8(c) % uint8(d))])
   218  (Mod16u (Const16 [c]) (Const16 [d])) && d != 0 => (Const16 [int16(uint16(c) % uint16(d))])
   219  (Mod32u (Const32 [c]) (Const32 [d])) && d != 0 => (Const32 [int32(uint32(c) % uint32(d))])
   220  (Mod64u (Const64 [c]) (Const64 [d])) && d != 0 => (Const64 [int64(uint64(c) % uint64(d))])
   221  
   222  (Lsh64x64  (Const64 [c]) (Const64 [d])) => (Const64 [c << uint64(d)])
   223  (Rsh64x64  (Const64 [c]) (Const64 [d])) => (Const64 [c >> uint64(d)])
   224  (Rsh64Ux64 (Const64 [c]) (Const64 [d])) => (Const64 [int64(uint64(c) >> uint64(d))])
   225  (Lsh32x64  (Const32 [c]) (Const64 [d])) => (Const32 [c << uint64(d)])
   226  (Rsh32x64  (Const32 [c]) (Const64 [d])) => (Const32 [c >> uint64(d)])
   227  (Rsh32Ux64 (Const32 [c]) (Const64 [d])) => (Const32 [int32(uint32(c) >> uint64(d))])
   228  (Lsh16x64  (Const16 [c]) (Const64 [d])) => (Const16 [c << uint64(d)])
   229  (Rsh16x64  (Const16 [c]) (Const64 [d])) => (Const16 [c >> uint64(d)])
   230  (Rsh16Ux64 (Const16 [c]) (Const64 [d])) => (Const16 [int16(uint16(c) >> uint64(d))])
   231  (Lsh8x64   (Const8  [c]) (Const64 [d])) => (Const8  [c << uint64(d)])
   232  (Rsh8x64   (Const8  [c]) (Const64 [d])) => (Const8  [c >> uint64(d)])
   233  (Rsh8Ux64  (Const8  [c]) (Const64 [d])) => (Const8  [int8(uint8(c) >> uint64(d))])
   234  
   235  // Fold IsInBounds when the range of the index cannot exceed the limit.
   236  (IsInBounds (ZeroExt8to32  _) (Const32 [c])) && (1 << 8)  <= c => (ConstBool [true])
   237  (IsInBounds (ZeroExt8to64  _) (Const64 [c])) && (1 << 8)  <= c => (ConstBool [true])
   238  (IsInBounds (ZeroExt16to32 _) (Const32 [c])) && (1 << 16) <= c => (ConstBool [true])
   239  (IsInBounds (ZeroExt16to64 _) (Const64 [c])) && (1 << 16) <= c => (ConstBool [true])
   240  (IsInBounds x x) => (ConstBool [false])
   241  (IsInBounds                (And8  (Const8  [c]) _)  (Const8  [d])) && 0 <= c && c < d => (ConstBool [true])
   242  (IsInBounds (ZeroExt8to16  (And8  (Const8  [c]) _)) (Const16 [d])) && 0 <= c && int16(c) < d => (ConstBool [true])
   243  (IsInBounds (ZeroExt8to32  (And8  (Const8  [c]) _)) (Const32 [d])) && 0 <= c && int32(c) < d => (ConstBool [true])
   244  (IsInBounds (ZeroExt8to64  (And8  (Const8  [c]) _)) (Const64 [d])) && 0 <= c && int64(c) < d => (ConstBool [true])
   245  (IsInBounds                (And16 (Const16 [c]) _)  (Const16 [d])) && 0 <= c && c < d => (ConstBool [true])
   246  (IsInBounds (ZeroExt16to32 (And16 (Const16 [c]) _)) (Const32 [d])) && 0 <= c && int32(c) < d => (ConstBool [true])
   247  (IsInBounds (ZeroExt16to64 (And16 (Const16 [c]) _)) (Const64 [d])) && 0 <= c && int64(c) < d => (ConstBool [true])
   248  (IsInBounds                (And32 (Const32 [c]) _)  (Const32 [d])) && 0 <= c && c < d => (ConstBool [true])
   249  (IsInBounds (ZeroExt32to64 (And32 (Const32 [c]) _)) (Const64 [d])) && 0 <= c && int64(c) < d => (ConstBool [true])
   250  (IsInBounds                (And64 (Const64 [c]) _)  (Const64 [d])) && 0 <= c && c < d => (ConstBool [true])
   251  (IsInBounds (Const32 [c]) (Const32 [d])) => (ConstBool [0 <= c && c < d])
   252  (IsInBounds (Const64 [c]) (Const64 [d])) => (ConstBool [0 <= c && c < d])
   253  // (Mod64u x y) is always between 0 (inclusive) and y (exclusive).
   254  (IsInBounds (Mod32u _ y) y) => (ConstBool [true])
   255  (IsInBounds (Mod64u _ y) y) => (ConstBool [true])
   256  // Right shifting an unsigned number limits its value.
   257  (IsInBounds (ZeroExt8to64  (Rsh8Ux64  _ (Const64 [c]))) (Const64 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   258  (IsInBounds (ZeroExt8to32  (Rsh8Ux64  _ (Const64 [c]))) (Const32 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   259  (IsInBounds (ZeroExt8to16  (Rsh8Ux64  _ (Const64 [c]))) (Const16 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   260  (IsInBounds                (Rsh8Ux64  _ (Const64 [c]))  (Const64 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   261  (IsInBounds (ZeroExt16to64 (Rsh16Ux64 _ (Const64 [c]))) (Const64 [d])) && 0 < c && c < 16 && 1<<uint(16-c)-1 < d => (ConstBool [true])
   262  (IsInBounds (ZeroExt16to32 (Rsh16Ux64 _ (Const64 [c]))) (Const64 [d])) && 0 < c && c < 16 && 1<<uint(16-c)-1 < d => (ConstBool [true])
   263  (IsInBounds                (Rsh16Ux64 _ (Const64 [c]))  (Const64 [d])) && 0 < c && c < 16 && 1<<uint(16-c)-1 < d => (ConstBool [true])
   264  (IsInBounds (ZeroExt32to64 (Rsh32Ux64 _ (Const64 [c]))) (Const64 [d])) && 0 < c && c < 32 && 1<<uint(32-c)-1 < d => (ConstBool [true])
   265  (IsInBounds                (Rsh32Ux64 _ (Const64 [c]))  (Const64 [d])) && 0 < c && c < 32 && 1<<uint(32-c)-1 < d => (ConstBool [true])
   266  (IsInBounds                (Rsh64Ux64 _ (Const64 [c]))  (Const64 [d])) && 0 < c && c < 64 && 1<<uint(64-c)-1 < d => (ConstBool [true])
   267  
   268  (IsSliceInBounds x x) => (ConstBool [true])
   269  (IsSliceInBounds (And32 (Const32 [c]) _) (Const32 [d])) && 0 <= c && c <= d => (ConstBool [true])
   270  (IsSliceInBounds (And64 (Const64 [c]) _) (Const64 [d])) && 0 <= c && c <= d => (ConstBool [true])
   271  (IsSliceInBounds (Const32 [0]) _) => (ConstBool [true])
   272  (IsSliceInBounds (Const64 [0]) _) => (ConstBool [true])
   273  (IsSliceInBounds (Const32 [c]) (Const32 [d])) => (ConstBool [0 <= c && c <= d])
   274  (IsSliceInBounds (Const64 [c]) (Const64 [d])) => (ConstBool [0 <= c && c <= d])
   275  (IsSliceInBounds (SliceLen x) (SliceCap x)) => (ConstBool [true])
   276  
   277  (Eq(64|32|16|8) x x) => (ConstBool [true])
   278  (EqB (ConstBool [c]) (ConstBool [d])) => (ConstBool [c == d])
   279  (EqB (ConstBool [false]) x) => (Not x)
   280  (EqB (ConstBool [true]) x) => x
   281  
   282  (Neq(64|32|16|8) x x) => (ConstBool [false])
   283  (NeqB (ConstBool [c]) (ConstBool [d])) => (ConstBool [c != d])
   284  (NeqB (ConstBool [false]) x) => x
   285  (NeqB (ConstBool [true]) x) => (Not x)
   286  (NeqB (Not x) (Not y)) => (NeqB x y)
   287  
   288  (Eq64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Eq64 (Const64 <t> [c-d]) x)
   289  (Eq32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Eq32 (Const32 <t> [c-d]) x)
   290  (Eq16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Eq16 (Const16 <t> [c-d]) x)
   291  (Eq8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Eq8  (Const8  <t> [c-d]) x)
   292  
   293  (Neq64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Neq64 (Const64 <t> [c-d]) x)
   294  (Neq32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Neq32 (Const32 <t> [c-d]) x)
   295  (Neq16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Neq16 (Const16 <t> [c-d]) x)
   296  (Neq8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Neq8  (Const8  <t> [c-d]) x)
   297  
   298  (CondSelect x _ (ConstBool [true ])) => x
   299  (CondSelect _ y (ConstBool [false])) => y
   300  (CondSelect x x _) => x
   301  
   302  // signed integer range: ( c <= x && x (<|<=) d ) -> ( unsigned(x-c) (<|<=) unsigned(d-c) )
   303  (AndB (Leq64 (Const64 [c]) x) ((Less|Leq)64 x (Const64 [d]))) && d >= c => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c])) (Const64 <x.Type> [d-c]))
   304  (AndB (Leq32 (Const32 [c]) x) ((Less|Leq)32 x (Const32 [d]))) && d >= c => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c])) (Const32 <x.Type> [d-c]))
   305  (AndB (Leq16 (Const16 [c]) x) ((Less|Leq)16 x (Const16 [d]))) && d >= c => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c])) (Const16 <x.Type> [d-c]))
   306  (AndB (Leq8  (Const8  [c]) x) ((Less|Leq)8  x (Const8  [d]))) && d >= c => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c])) (Const8  <x.Type> [d-c]))
   307  
   308  // signed integer range: ( c < x && x (<|<=) d ) -> ( unsigned(x-(c+1)) (<|<=) unsigned(d-(c+1)) )
   309  (AndB (Less64 (Const64 [c]) x) ((Less|Leq)64 x (Const64 [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c+1])) (Const64 <x.Type> [d-c-1]))
   310  (AndB (Less32 (Const32 [c]) x) ((Less|Leq)32 x (Const32 [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c+1])) (Const32 <x.Type> [d-c-1]))
   311  (AndB (Less16 (Const16 [c]) x) ((Less|Leq)16 x (Const16 [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c+1])) (Const16 <x.Type> [d-c-1]))
   312  (AndB (Less8  (Const8  [c]) x) ((Less|Leq)8  x (Const8  [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c+1])) (Const8  <x.Type> [d-c-1]))
   313  
   314  // unsigned integer range: ( c <= x && x (<|<=) d ) -> ( x-c (<|<=) d-c )
   315  (AndB (Leq64U (Const64 [c]) x) ((Less|Leq)64U x (Const64 [d]))) && uint64(d) >= uint64(c) => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c])) (Const64 <x.Type> [d-c]))
   316  (AndB (Leq32U (Const32 [c]) x) ((Less|Leq)32U x (Const32 [d]))) && uint32(d) >= uint32(c) => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c])) (Const32 <x.Type> [d-c]))
   317  (AndB (Leq16U (Const16 [c]) x) ((Less|Leq)16U x (Const16 [d]))) && uint16(d) >= uint16(c) => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c])) (Const16 <x.Type> [d-c]))
   318  (AndB (Leq8U  (Const8  [c]) x) ((Less|Leq)8U  x (Const8  [d]))) && uint8(d)  >= uint8(c)  => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c])) (Const8  <x.Type> [d-c]))
   319  
   320  // unsigned integer range: ( c < x && x (<|<=) d ) -> ( x-(c+1) (<|<=) d-(c+1) )
   321  (AndB (Less64U (Const64 [c]) x) ((Less|Leq)64U x (Const64 [d]))) && uint64(d) >= uint64(c+1) && uint64(c+1) > uint64(c) => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c+1])) (Const64 <x.Type> [d-c-1]))
   322  (AndB (Less32U (Const32 [c]) x) ((Less|Leq)32U x (Const32 [d]))) && uint32(d) >= uint32(c+1) && uint32(c+1) > uint32(c) => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c+1])) (Const32 <x.Type> [d-c-1]))
   323  (AndB (Less16U (Const16 [c]) x) ((Less|Leq)16U x (Const16 [d]))) && uint16(d) >= uint16(c+1) && uint16(c+1) > uint16(c) => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c+1])) (Const16 <x.Type> [d-c-1]))
   324  (AndB (Less8U  (Const8  [c]) x) ((Less|Leq)8U  x (Const8  [d]))) && uint8(d)  >= uint8(c+1)  && uint8(c+1)  > uint8(c)  => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c+1]))  (Const8  <x.Type> [d-c-1]))
   325  
   326  // signed integer range: ( c (<|<=) x || x < d ) -> ( unsigned(c-d) (<|<=) unsigned(x-d) )
   327  (OrB ((Less|Leq)64 (Const64 [c]) x) (Less64 x (Const64 [d]))) && c >= d => ((Less|Leq)64U (Const64 <x.Type> [c-d]) (Sub64 <x.Type> x (Const64 <x.Type> [d])))
   328  (OrB ((Less|Leq)32 (Const32 [c]) x) (Less32 x (Const32 [d]))) && c >= d => ((Less|Leq)32U (Const32 <x.Type> [c-d]) (Sub32 <x.Type> x (Const32 <x.Type> [d])))
   329  (OrB ((Less|Leq)16 (Const16 [c]) x) (Less16 x (Const16 [d]))) && c >= d => ((Less|Leq)16U (Const16 <x.Type> [c-d]) (Sub16 <x.Type> x (Const16 <x.Type> [d])))
   330  (OrB ((Less|Leq)8  (Const8  [c]) x) (Less8  x (Const8  [d]))) && c >= d => ((Less|Leq)8U  (Const8  <x.Type> [c-d]) (Sub8  <x.Type> x (Const8  <x.Type> [d])))
   331  
   332  // signed integer range: ( c (<|<=) x || x <= d ) -> ( unsigned(c-(d+1)) (<|<=) unsigned(x-(d+1)) )
   333  (OrB ((Less|Leq)64 (Const64 [c]) x) (Leq64 x (Const64 [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)64U (Const64 <x.Type> [c-d-1]) (Sub64 <x.Type> x (Const64 <x.Type> [d+1])))
   334  (OrB ((Less|Leq)32 (Const32 [c]) x) (Leq32 x (Const32 [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)32U (Const32 <x.Type> [c-d-1]) (Sub32 <x.Type> x (Const32 <x.Type> [d+1])))
   335  (OrB ((Less|Leq)16 (Const16 [c]) x) (Leq16 x (Const16 [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)16U (Const16 <x.Type> [c-d-1]) (Sub16 <x.Type> x (Const16 <x.Type> [d+1])))
   336  (OrB ((Less|Leq)8  (Const8  [c]) x) (Leq8  x (Const8  [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)8U  (Const8  <x.Type> [c-d-1]) (Sub8  <x.Type> x (Const8  <x.Type> [d+1])))
   337  
   338  // unsigned integer range: ( c (<|<=) x || x < d ) -> ( c-d (<|<=) x-d )
   339  (OrB ((Less|Leq)64U (Const64 [c]) x) (Less64U x (Const64 [d]))) && uint64(c) >= uint64(d) => ((Less|Leq)64U (Const64 <x.Type> [c-d]) (Sub64 <x.Type> x (Const64 <x.Type> [d])))
   340  (OrB ((Less|Leq)32U (Const32 [c]) x) (Less32U x (Const32 [d]))) && uint32(c) >= uint32(d) => ((Less|Leq)32U (Const32 <x.Type> [c-d]) (Sub32 <x.Type> x (Const32 <x.Type> [d])))
   341  (OrB ((Less|Leq)16U (Const16 [c]) x) (Less16U x (Const16 [d]))) && uint16(c) >= uint16(d) => ((Less|Leq)16U (Const16 <x.Type> [c-d]) (Sub16 <x.Type> x (Const16 <x.Type> [d])))
   342  (OrB ((Less|Leq)8U  (Const8  [c]) x) (Less8U  x (Const8  [d]))) && uint8(c)  >= uint8(d)  => ((Less|Leq)8U  (Const8  <x.Type> [c-d]) (Sub8  <x.Type> x (Const8  <x.Type> [d])))
   343  
   344  // unsigned integer range: ( c (<|<=) x || x <= d ) -> ( c-(d+1) (<|<=) x-(d+1) )
   345  (OrB ((Less|Leq)64U (Const64 [c]) x) (Leq64U x (Const64 [d]))) && uint64(c) >= uint64(d+1) && uint64(d+1) > uint64(d) => ((Less|Leq)64U (Const64 <x.Type> [c-d-1]) (Sub64 <x.Type> x (Const64 <x.Type> [d+1])))
   346  (OrB ((Less|Leq)32U (Const32 [c]) x) (Leq32U x (Const32 [d]))) && uint32(c) >= uint32(d+1) && uint32(d+1) > uint32(d) => ((Less|Leq)32U (Const32 <x.Type> [c-d-1]) (Sub32 <x.Type> x (Const32 <x.Type> [d+1])))
   347  (OrB ((Less|Leq)16U (Const16 [c]) x) (Leq16U x (Const16 [d]))) && uint16(c) >= uint16(d+1) && uint16(d+1) > uint16(d) => ((Less|Leq)16U (Const16 <x.Type> [c-d-1]) (Sub16 <x.Type> x (Const16 <x.Type> [d+1])))
   348  (OrB ((Less|Leq)8U  (Const8  [c]) x) (Leq8U  x (Const8  [d]))) && uint8(c)  >= uint8(d+1)  && uint8(d+1)  > uint8(d)  => ((Less|Leq)8U  (Const8  <x.Type> [c-d-1]) (Sub8  <x.Type> x (Const8  <x.Type> [d+1])))
   349  
   350  // NaN check: ( x != x || x (>|>=|<|<=) c ) -> ( !(c (>=|>|<=|<) x) )
   351  (OrB (Neq64F x x) ((Less|Leq)64F x y:(Const64F [c]))) => (Not ((Leq|Less)64F y x))
   352  (OrB (Neq64F x x) ((Less|Leq)64F y:(Const64F [c]) x)) => (Not ((Leq|Less)64F x y))
   353  (OrB (Neq32F x x) ((Less|Leq)32F x y:(Const32F [c]))) => (Not ((Leq|Less)32F y x))
   354  (OrB (Neq32F x x) ((Less|Leq)32F y:(Const32F [c]) x)) => (Not ((Leq|Less)32F x y))
   355  
   356  // NaN check: ( x != x || Abs(x) (>|>=|<|<=) c ) -> ( !(c (>=|>|<=|<) Abs(x) )
   357  (OrB (Neq64F x x) ((Less|Leq)64F abs:(Abs x) y:(Const64F [c]))) => (Not ((Leq|Less)64F y abs))
   358  (OrB (Neq64F x x) ((Less|Leq)64F y:(Const64F [c]) abs:(Abs x))) => (Not ((Leq|Less)64F abs y))
   359  
   360  // NaN check: ( x != x || -x (>|>=|<|<=) c ) -> ( !(c (>=|>|<=|<) -x) )
   361  (OrB (Neq64F x x) ((Less|Leq)64F neg:(Neg64F x) y:(Const64F [c]))) => (Not ((Leq|Less)64F y neg))
   362  (OrB (Neq64F x x) ((Less|Leq)64F y:(Const64F [c]) neg:(Neg64F x))) => (Not ((Leq|Less)64F neg y))
   363  (OrB (Neq32F x x) ((Less|Leq)32F neg:(Neg32F x) y:(Const32F [c]))) => (Not ((Leq|Less)32F y neg))
   364  (OrB (Neq32F x x) ((Less|Leq)32F y:(Const32F [c]) neg:(Neg32F x))) => (Not ((Leq|Less)32F neg y))
   365  
   366  // Canonicalize x-const to x+(-const)
   367  (Sub64 x (Const64 <t> [c])) && x.Op != OpConst64 => (Add64 (Const64 <t> [-c]) x)
   368  (Sub32 x (Const32 <t> [c])) && x.Op != OpConst32 => (Add32 (Const32 <t> [-c]) x)
   369  (Sub16 x (Const16 <t> [c])) && x.Op != OpConst16 => (Add16 (Const16 <t> [-c]) x)
   370  (Sub8  x (Const8  <t> [c])) && x.Op != OpConst8  => (Add8  (Const8  <t> [-c]) x)
   371  
   372  // fold negation into comparison operators
   373  (Not (Eq(64|32|16|8|B|Ptr|64F|32F) x y)) => (Neq(64|32|16|8|B|Ptr|64F|32F) x y)
   374  (Not (Neq(64|32|16|8|B|Ptr|64F|32F) x y)) => (Eq(64|32|16|8|B|Ptr|64F|32F) x y)
   375  
   376  (Not (Less(64|32|16|8) x y)) => (Leq(64|32|16|8) y x)
   377  (Not (Less(64|32|16|8)U x y)) => (Leq(64|32|16|8)U y x)
   378  (Not (Leq(64|32|16|8) x y)) => (Less(64|32|16|8) y x)
   379  (Not (Leq(64|32|16|8)U x y)) => (Less(64|32|16|8)U y x)
   380  
   381  // Distribute multiplication c * (d+x) -> c*d + c*x. Useful for:
   382  // a[i].b = ...; a[i+1].b = ...
   383  (Mul64 (Const64 <t> [c]) (Add64 <t> (Const64 <t> [d]) x)) =>
   384    (Add64 (Const64 <t> [c*d]) (Mul64 <t> (Const64 <t> [c]) x))
   385  (Mul32 (Const32 <t> [c]) (Add32 <t> (Const32 <t> [d]) x)) =>
   386    (Add32 (Const32 <t> [c*d]) (Mul32 <t> (Const32 <t> [c]) x))
   387  (Mul16 (Const16 <t> [c]) (Add16 <t> (Const16 <t> [d]) x)) =>
   388    (Add16 (Const16 <t> [c*d]) (Mul16 <t> (Const16 <t> [c]) x))
   389  (Mul8 (Const8 <t> [c]) (Add8 <t> (Const8 <t> [d]) x)) =>
   390    (Add8 (Const8 <t> [c*d]) (Mul8 <t> (Const8 <t> [c]) x))
   391  
   392  // Rewrite x*y ± x*z  to  x*(y±z)
   393  (Add(64|32|16|8) <t> (Mul(64|32|16|8) x y) (Mul(64|32|16|8) x z))
   394  	=> (Mul(64|32|16|8) x (Add(64|32|16|8) <t> y z))
   395  (Sub(64|32|16|8) <t> (Mul(64|32|16|8) x y) (Mul(64|32|16|8) x z))
   396  	=> (Mul(64|32|16|8) x (Sub(64|32|16|8) <t> y z))
   397  
   398  // rewrite shifts of 8/16/32 bit consts into 64 bit consts to reduce
   399  // the number of the other rewrite rules for const shifts
   400  (Lsh64x32  <t> x (Const32 [c])) => (Lsh64x64  x (Const64 <t> [int64(uint32(c))]))
   401  (Lsh64x16  <t> x (Const16 [c])) => (Lsh64x64  x (Const64 <t> [int64(uint16(c))]))
   402  (Lsh64x8   <t> x (Const8  [c])) => (Lsh64x64  x (Const64 <t> [int64(uint8(c))]))
   403  (Rsh64x32  <t> x (Const32 [c])) => (Rsh64x64  x (Const64 <t> [int64(uint32(c))]))
   404  (Rsh64x16  <t> x (Const16 [c])) => (Rsh64x64  x (Const64 <t> [int64(uint16(c))]))
   405  (Rsh64x8   <t> x (Const8  [c])) => (Rsh64x64  x (Const64 <t> [int64(uint8(c))]))
   406  (Rsh64Ux32 <t> x (Const32 [c])) => (Rsh64Ux64 x (Const64 <t> [int64(uint32(c))]))
   407  (Rsh64Ux16 <t> x (Const16 [c])) => (Rsh64Ux64 x (Const64 <t> [int64(uint16(c))]))
   408  (Rsh64Ux8  <t> x (Const8  [c])) => (Rsh64Ux64 x (Const64 <t> [int64(uint8(c))]))
   409  
   410  (Lsh32x32  <t> x (Const32 [c])) => (Lsh32x64  x (Const64 <t> [int64(uint32(c))]))
   411  (Lsh32x16  <t> x (Const16 [c])) => (Lsh32x64  x (Const64 <t> [int64(uint16(c))]))
   412  (Lsh32x8   <t> x (Const8  [c])) => (Lsh32x64  x (Const64 <t> [int64(uint8(c))]))
   413  (Rsh32x32  <t> x (Const32 [c])) => (Rsh32x64  x (Const64 <t> [int64(uint32(c))]))
   414  (Rsh32x16  <t> x (Const16 [c])) => (Rsh32x64  x (Const64 <t> [int64(uint16(c))]))
   415  (Rsh32x8   <t> x (Const8  [c])) => (Rsh32x64  x (Const64 <t> [int64(uint8(c))]))
   416  (Rsh32Ux32 <t> x (Const32 [c])) => (Rsh32Ux64 x (Const64 <t> [int64(uint32(c))]))
   417  (Rsh32Ux16 <t> x (Const16 [c])) => (Rsh32Ux64 x (Const64 <t> [int64(uint16(c))]))
   418  (Rsh32Ux8  <t> x (Const8  [c])) => (Rsh32Ux64 x (Const64 <t> [int64(uint8(c))]))
   419  
   420  (Lsh16x32  <t> x (Const32 [c])) => (Lsh16x64  x (Const64 <t> [int64(uint32(c))]))
   421  (Lsh16x16  <t> x (Const16 [c])) => (Lsh16x64  x (Const64 <t> [int64(uint16(c))]))
   422  (Lsh16x8   <t> x (Const8  [c])) => (Lsh16x64  x (Const64 <t> [int64(uint8(c))]))
   423  (Rsh16x32  <t> x (Const32 [c])) => (Rsh16x64  x (Const64 <t> [int64(uint32(c))]))
   424  (Rsh16x16  <t> x (Const16 [c])) => (Rsh16x64  x (Const64 <t> [int64(uint16(c))]))
   425  (Rsh16x8   <t> x (Const8  [c])) => (Rsh16x64  x (Const64 <t> [int64(uint8(c))]))
   426  (Rsh16Ux32 <t> x (Const32 [c])) => (Rsh16Ux64 x (Const64 <t> [int64(uint32(c))]))
   427  (Rsh16Ux16 <t> x (Const16 [c])) => (Rsh16Ux64 x (Const64 <t> [int64(uint16(c))]))
   428  (Rsh16Ux8  <t> x (Const8  [c])) => (Rsh16Ux64 x (Const64 <t> [int64(uint8(c))]))
   429  
   430  (Lsh8x32  <t> x (Const32 [c])) => (Lsh8x64  x (Const64 <t> [int64(uint32(c))]))
   431  (Lsh8x16  <t> x (Const16 [c])) => (Lsh8x64  x (Const64 <t> [int64(uint16(c))]))
   432  (Lsh8x8   <t> x (Const8  [c])) => (Lsh8x64  x (Const64 <t> [int64(uint8(c))]))
   433  (Rsh8x32  <t> x (Const32 [c])) => (Rsh8x64  x (Const64 <t> [int64(uint32(c))]))
   434  (Rsh8x16  <t> x (Const16 [c])) => (Rsh8x64  x (Const64 <t> [int64(uint16(c))]))
   435  (Rsh8x8   <t> x (Const8  [c])) => (Rsh8x64  x (Const64 <t> [int64(uint8(c))]))
   436  (Rsh8Ux32 <t> x (Const32 [c])) => (Rsh8Ux64 x (Const64 <t> [int64(uint32(c))]))
   437  (Rsh8Ux16 <t> x (Const16 [c])) => (Rsh8Ux64 x (Const64 <t> [int64(uint16(c))]))
   438  (Rsh8Ux8  <t> x (Const8  [c])) => (Rsh8Ux64 x (Const64 <t> [int64(uint8(c))]))
   439  
   440  // shifts by zero
   441  (Lsh(64|32|16|8)x64  x (Const64 [0])) => x
   442  (Rsh(64|32|16|8)x64  x (Const64 [0])) => x
   443  (Rsh(64|32|16|8)Ux64 x (Const64 [0])) => x
   444  
   445  // rotates by multiples of register width
   446  (RotateLeft64 x (Const64 [c])) && c%64 == 0 => x
   447  (RotateLeft32 x (Const32 [c])) && c%32 == 0 => x
   448  (RotateLeft16 x (Const16 [c])) && c%16 == 0 => x
   449  (RotateLeft8  x (Const8 [c]))  && c%8  == 0 => x
   450  
   451  // zero shifted
   452  (Lsh64x(64|32|16|8)  (Const64 [0]) _) => (Const64 [0])
   453  (Rsh64x(64|32|16|8)  (Const64 [0]) _) => (Const64 [0])
   454  (Rsh64Ux(64|32|16|8) (Const64 [0]) _) => (Const64 [0])
   455  (Lsh32x(64|32|16|8)  (Const32 [0]) _) => (Const32 [0])
   456  (Rsh32x(64|32|16|8)  (Const32 [0]) _) => (Const32 [0])
   457  (Rsh32Ux(64|32|16|8) (Const32 [0]) _) => (Const32 [0])
   458  (Lsh16x(64|32|16|8)  (Const16 [0]) _) => (Const16 [0])
   459  (Rsh16x(64|32|16|8)  (Const16 [0]) _) => (Const16 [0])
   460  (Rsh16Ux(64|32|16|8) (Const16 [0]) _) => (Const16 [0])
   461  (Lsh8x(64|32|16|8)   (Const8  [0]) _) => (Const8  [0])
   462  (Rsh8x(64|32|16|8)   (Const8  [0]) _) => (Const8  [0])
   463  (Rsh8Ux(64|32|16|8)  (Const8  [0]) _) => (Const8  [0])
   464  
   465  // large left shifts of all values, and right shifts of unsigned values
   466  ((Lsh64|Rsh64U)x64  _ (Const64 [c])) && uint64(c) >= 64 => (Const64 [0])
   467  ((Lsh32|Rsh32U)x64  _ (Const64 [c])) && uint64(c) >= 32 => (Const32 [0])
   468  ((Lsh16|Rsh16U)x64  _ (Const64 [c])) && uint64(c) >= 16 => (Const16 [0])
   469  ((Lsh8|Rsh8U)x64    _ (Const64 [c])) && uint64(c) >= 8  => (Const8  [0])
   470  
   471  // combine const shifts
   472  (Lsh64x64 <t> (Lsh64x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh64x64 x (Const64 <t> [c+d]))
   473  (Lsh32x64 <t> (Lsh32x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh32x64 x (Const64 <t> [c+d]))
   474  (Lsh16x64 <t> (Lsh16x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh16x64 x (Const64 <t> [c+d]))
   475  (Lsh8x64  <t> (Lsh8x64  x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh8x64  x (Const64 <t> [c+d]))
   476  
   477  (Rsh64x64 <t> (Rsh64x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh64x64 x (Const64 <t> [c+d]))
   478  (Rsh32x64 <t> (Rsh32x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh32x64 x (Const64 <t> [c+d]))
   479  (Rsh16x64 <t> (Rsh16x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh16x64 x (Const64 <t> [c+d]))
   480  (Rsh8x64  <t> (Rsh8x64  x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh8x64  x (Const64 <t> [c+d]))
   481  
   482  (Rsh64Ux64 <t> (Rsh64Ux64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh64Ux64 x (Const64 <t> [c+d]))
   483  (Rsh32Ux64 <t> (Rsh32Ux64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh32Ux64 x (Const64 <t> [c+d]))
   484  (Rsh16Ux64 <t> (Rsh16Ux64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh16Ux64 x (Const64 <t> [c+d]))
   485  (Rsh8Ux64  <t> (Rsh8Ux64  x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh8Ux64  x (Const64 <t> [c+d]))
   486  
   487  // Remove signed right shift before an unsigned right shift that extracts the sign bit.
   488  (Rsh8Ux64  (Rsh8x64  x _) (Const64 <t> [7] )) => (Rsh8Ux64  x (Const64 <t> [7] ))
   489  (Rsh16Ux64 (Rsh16x64 x _) (Const64 <t> [15])) => (Rsh16Ux64 x (Const64 <t> [15]))
   490  (Rsh32Ux64 (Rsh32x64 x _) (Const64 <t> [31])) => (Rsh32Ux64 x (Const64 <t> [31]))
   491  (Rsh64Ux64 (Rsh64x64 x _) (Const64 <t> [63])) => (Rsh64Ux64 x (Const64 <t> [63]))
   492  
   493  // Convert x>>c<<c to x&^(1<<c-1)
   494  (Lsh64x64 i:(Rsh(64|64U)x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 64 && i.Uses == 1 => (And64 x (Const64 <v.Type> [int64(-1) << c]))
   495  (Lsh32x64 i:(Rsh(32|32U)x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 32 && i.Uses == 1 => (And32 x (Const32 <v.Type> [int32(-1) << c]))
   496  (Lsh16x64 i:(Rsh(16|16U)x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 16 && i.Uses == 1 => (And16 x (Const16 <v.Type> [int16(-1) << c]))
   497  (Lsh8x64  i:(Rsh(8|8U)x64    x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 8  && i.Uses == 1 => (And8  x (Const8  <v.Type> [int8(-1)  << c]))
   498  // similarly for x<<c>>c
   499  (Rsh64Ux64 i:(Lsh64x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 64 && i.Uses == 1 => (And64 x (Const64 <v.Type> [int64(^uint64(0)>>c)]))
   500  (Rsh32Ux64 i:(Lsh32x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 32 && i.Uses == 1 => (And32 x (Const32 <v.Type> [int32(^uint32(0)>>c)]))
   501  (Rsh16Ux64 i:(Lsh16x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 16 && i.Uses == 1 => (And16 x (Const16 <v.Type> [int16(^uint16(0)>>c)]))
   502  (Rsh8Ux64  i:(Lsh8x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 8  && i.Uses == 1 => (And8  x (Const8  <v.Type> [int8 (^uint8 (0)>>c)]))
   503  
   504  // ((x >> c1) << c2) >> c3
   505  (Rsh(64|32|16|8)Ux64 (Lsh(64|32|16|8)x64 (Rsh(64|32|16|8)Ux64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
   506    && uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
   507    => (Rsh(64|32|16|8)Ux64 x (Const64 <typ.UInt64> [c1-c2+c3]))
   508  
   509  // ((x << c1) >> c2) << c3
   510  (Lsh(64|32|16|8)x64 (Rsh(64|32|16|8)Ux64 (Lsh(64|32|16|8)x64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
   511    && uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
   512    => (Lsh(64|32|16|8)x64 x (Const64 <typ.UInt64> [c1-c2+c3]))
   513  
   514  // (x >> c) & uppermask = 0
   515  (And64 (Const64 [m]) (Rsh64Ux64 _ (Const64 [c]))) && c >= int64(64-ntz64(m)) => (Const64 [0])
   516  (And32 (Const32 [m]) (Rsh32Ux64 _ (Const64 [c]))) && c >= int64(32-ntz32(m)) => (Const32 [0])
   517  (And16 (Const16 [m]) (Rsh16Ux64 _ (Const64 [c]))) && c >= int64(16-ntz16(m)) => (Const16 [0])
   518  (And8  (Const8  [m]) (Rsh8Ux64  _ (Const64 [c]))) && c >= int64(8-ntz8(m))  => (Const8  [0])
   519  
   520  // (x << c) & lowermask = 0
   521  (And64 (Const64 [m]) (Lsh64x64  _ (Const64 [c]))) && c >= int64(64-nlz64(m)) => (Const64 [0])
   522  (And32 (Const32 [m]) (Lsh32x64  _ (Const64 [c]))) && c >= int64(32-nlz32(m)) => (Const32 [0])
   523  (And16 (Const16 [m]) (Lsh16x64  _ (Const64 [c]))) && c >= int64(16-nlz16(m)) => (Const16 [0])
   524  (And8  (Const8  [m]) (Lsh8x64   _ (Const64 [c]))) && c >= int64(8-nlz8(m))  => (Const8  [0])
   525  
   526  // replace shifts with zero extensions
   527  (Rsh16Ux64 (Lsh16x64 x (Const64  [8])) (Const64  [8])) => (ZeroExt8to16  (Trunc16to8  <typ.UInt8>  x))
   528  (Rsh32Ux64 (Lsh32x64 x (Const64 [24])) (Const64 [24])) => (ZeroExt8to32  (Trunc32to8  <typ.UInt8>  x))
   529  (Rsh64Ux64 (Lsh64x64 x (Const64 [56])) (Const64 [56])) => (ZeroExt8to64  (Trunc64to8  <typ.UInt8>  x))
   530  (Rsh32Ux64 (Lsh32x64 x (Const64 [16])) (Const64 [16])) => (ZeroExt16to32 (Trunc32to16 <typ.UInt16> x))
   531  (Rsh64Ux64 (Lsh64x64 x (Const64 [48])) (Const64 [48])) => (ZeroExt16to64 (Trunc64to16 <typ.UInt16> x))
   532  (Rsh64Ux64 (Lsh64x64 x (Const64 [32])) (Const64 [32])) => (ZeroExt32to64 (Trunc64to32 <typ.UInt32> x))
   533  
   534  // replace shifts with sign extensions
   535  (Rsh16x64 (Lsh16x64 x (Const64  [8])) (Const64  [8])) => (SignExt8to16  (Trunc16to8  <typ.Int8>  x))
   536  (Rsh32x64 (Lsh32x64 x (Const64 [24])) (Const64 [24])) => (SignExt8to32  (Trunc32to8  <typ.Int8>  x))
   537  (Rsh64x64 (Lsh64x64 x (Const64 [56])) (Const64 [56])) => (SignExt8to64  (Trunc64to8  <typ.Int8>  x))
   538  (Rsh32x64 (Lsh32x64 x (Const64 [16])) (Const64 [16])) => (SignExt16to32 (Trunc32to16 <typ.Int16> x))
   539  (Rsh64x64 (Lsh64x64 x (Const64 [48])) (Const64 [48])) => (SignExt16to64 (Trunc64to16 <typ.Int16> x))
   540  (Rsh64x64 (Lsh64x64 x (Const64 [32])) (Const64 [32])) => (SignExt32to64 (Trunc64to32 <typ.Int32> x))
   541  
   542  // ((x >> c) & d) << e
   543  (Lsh64x64 (And64 (Rsh(64|64U)x64 <t> x (Const64 <t2> [c])) (Const64 [d])) (Const64 [e])) && c >= e => (And64 (Rsh(64|64U)x64 <t> x (Const64 <t2> [c-e])) (Const64 <t> [d<<e]))
   544  (Lsh32x64 (And32 (Rsh(32|32U)x64 <t> x (Const64 <t2> [c])) (Const32 [d])) (Const64 [e])) && c >= e => (And32 (Rsh(32|32U)x64 <t> x (Const64 <t2> [c-e])) (Const32 <t> [d<<e]))
   545  (Lsh16x64 (And16 (Rsh(16|16U)x64 <t> x (Const64 <t2> [c])) (Const16 [d])) (Const64 [e])) && c >= e => (And16 (Rsh(16|16U)x64 <t> x (Const64 <t2> [c-e])) (Const16 <t> [d<<e]))
   546  (Lsh8x64  (And8  (Rsh(8|8U)x64   <t> x (Const64 <t2> [c])) (Const8  [d])) (Const64 [e])) && c >= e => (And8  (Rsh(8|8U)x64   <t> x (Const64 <t2> [c-e])) (Const8  <t> [d<<e]))
   547  (Lsh64x64 (And64 (Rsh(64|64U)x64 <t> x (Const64 <t2> [c])) (Const64 [d])) (Const64 [e])) && c < e =>  (And64 (Lsh64x64 <t> x (Const64 <t2> [e-c])) (Const64 <t> [d<<e]))
   548  (Lsh32x64 (And32 (Rsh(32|32U)x64 <t> x (Const64 <t2> [c])) (Const32 [d])) (Const64 [e])) && c < e =>  (And32 (Lsh32x64 <t> x (Const64 <t2> [e-c])) (Const32 <t> [d<<e]))
   549  (Lsh16x64 (And16 (Rsh(16|16U)x64 <t> x (Const64 <t2> [c])) (Const16 [d])) (Const64 [e])) && c < e =>  (And16 (Lsh16x64 <t> x (Const64 <t2> [e-c])) (Const16 <t> [d<<e]))
   550  (Lsh8x64  (And8  (Rsh(8|8U)x64   <t> x (Const64 <t2> [c])) (Const8  [d])) (Const64 [e])) && c < e =>  (And8  (Lsh8x64  <t> x (Const64 <t2> [e-c])) (Const8  <t> [d<<e]))
   551  
   552  // constant comparisons
   553  (Eq(64|32|16|8)   (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c == d])
   554  (Neq(64|32|16|8)  (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c != d])
   555  (Less(64|32|16|8) (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c < d])
   556  (Leq(64|32|16|8)  (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c <= d])
   557  
   558  (Less64U (Const64 [c]) (Const64 [d])) => (ConstBool [uint64(c) < uint64(d)])
   559  (Less32U (Const32 [c]) (Const32 [d])) => (ConstBool [uint32(c) < uint32(d)])
   560  (Less16U (Const16 [c]) (Const16 [d])) => (ConstBool [uint16(c) < uint16(d)])
   561  (Less8U  (Const8  [c]) (Const8  [d])) => (ConstBool [ uint8(c) <  uint8(d)])
   562  
   563  (Leq64U (Const64 [c]) (Const64 [d])) => (ConstBool [uint64(c) <= uint64(d)])
   564  (Leq32U (Const32 [c]) (Const32 [d])) => (ConstBool [uint32(c) <= uint32(d)])
   565  (Leq16U (Const16 [c]) (Const16 [d])) => (ConstBool [uint16(c) <= uint16(d)])
   566  (Leq8U  (Const8  [c]) (Const8  [d])) => (ConstBool [ uint8(c) <=  uint8(d)])
   567  
   568  (Leq8  (Const8  [0]) (And8  _ (Const8  [c]))) && c >= 0 => (ConstBool [true])
   569  (Leq16 (Const16 [0]) (And16 _ (Const16 [c]))) && c >= 0 => (ConstBool [true])
   570  (Leq32 (Const32 [0]) (And32 _ (Const32 [c]))) && c >= 0 => (ConstBool [true])
   571  (Leq64 (Const64 [0]) (And64 _ (Const64 [c]))) && c >= 0 => (ConstBool [true])
   572  
   573  (Leq8  (Const8  [0]) (Rsh8Ux64  _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   574  (Leq16 (Const16 [0]) (Rsh16Ux64 _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   575  (Leq32 (Const32 [0]) (Rsh32Ux64 _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   576  (Leq64 (Const64 [0]) (Rsh64Ux64 _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   577  
   578  // prefer equalities with zero
   579  (Less(64|32|16|8) (Const(64|32|16|8) <t> [0]) x) && isNonNegative(x) => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   580  (Less(64|32|16|8) x (Const(64|32|16|8) <t> [1])) && isNonNegative(x) => (Eq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   581  (Less(64|32|16|8)U x (Const(64|32|16|8) <t> [1])) => (Eq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   582  (Leq(64|32|16|8)U (Const(64|32|16|8) <t> [1]) x) => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   583  
   584  // prefer comparisons with zero
   585  (Less(64|32|16|8) x (Const(64|32|16|8) <t> [1])) => (Leq(64|32|16|8) x (Const(64|32|16|8) <t> [0]))
   586  (Leq(64|32|16|8) x (Const(64|32|16|8) <t> [-1])) => (Less(64|32|16|8) x (Const(64|32|16|8) <t> [0]))
   587  (Leq(64|32|16|8) (Const(64|32|16|8) <t> [1]) x) => (Less(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   588  (Less(64|32|16|8) (Const(64|32|16|8) <t> [-1]) x) => (Leq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   589  
   590  // constant floating point comparisons
   591  (Eq32F   (Const32F [c]) (Const32F [d])) => (ConstBool [c == d])
   592  (Eq64F   (Const64F [c]) (Const64F [d])) => (ConstBool [c == d])
   593  (Neq32F  (Const32F [c]) (Const32F [d])) => (ConstBool [c != d])
   594  (Neq64F  (Const64F [c]) (Const64F [d])) => (ConstBool [c != d])
   595  (Less32F (Const32F [c]) (Const32F [d])) => (ConstBool [c < d])
   596  (Less64F (Const64F [c]) (Const64F [d])) => (ConstBool [c < d])
   597  (Leq32F  (Const32F [c]) (Const32F [d])) => (ConstBool [c <= d])
   598  (Leq64F  (Const64F [c]) (Const64F [d])) => (ConstBool [c <= d])
   599  
   600  // simplifications
   601  (Or(64|32|16|8) x x) => x
   602  (Or(64|32|16|8) (Const(64|32|16|8)  [0]) x) => x
   603  (Or(64|32|16|8) (Const(64|32|16|8) [-1]) _) => (Const(64|32|16|8) [-1])
   604  (Or(64|32|16|8) (Com(64|32|16|8)     x)  x) => (Const(64|32|16|8) [-1])
   605  
   606  (And(64|32|16|8) x x) => x
   607  (And(64|32|16|8) (Const(64|32|16|8) [-1]) x) => x
   608  (And(64|32|16|8) (Const(64|32|16|8)  [0]) _) => (Const(64|32|16|8) [0])
   609  (And(64|32|16|8) (Com(64|32|16|8)     x)  x) => (Const(64|32|16|8) [0])
   610  
   611  (Xor(64|32|16|8) x x) => (Const(64|32|16|8) [0])
   612  (Xor(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
   613  (Xor(64|32|16|8) (Com(64|32|16|8)    x)  x) => (Const(64|32|16|8) [-1])
   614  
   615  (Add(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
   616  (Sub(64|32|16|8) x x) => (Const(64|32|16|8) [0])
   617  (Mul(64|32|16|8) (Const(64|32|16|8) [0]) _) => (Const(64|32|16|8) [0])
   618  (Mul(64|32)uover <t> (Const(64|32) [0]) x) => (MakeTuple (Const(64|32) <t.FieldType(0)> [0]) (ConstBool <t.FieldType(1)> [false]))
   619  
   620  (Com(64|32|16|8) (Com(64|32|16|8)  x)) => x
   621  (Com(64|32|16|8) (Const(64|32|16|8) [c])) => (Const(64|32|16|8) [^c])
   622  
   623  (Neg(64|32|16|8) (Sub(64|32|16|8) x y)) => (Sub(64|32|16|8) y x)
   624  (Add(64|32|16|8) x (Neg(64|32|16|8) y)) => (Sub(64|32|16|8) x y)
   625  
   626  (Xor(64|32|16|8) (Const(64|32|16|8) [-1]) x) => (Com(64|32|16|8) x)
   627  
   628  (Sub(64|32|16|8) (Neg(64|32|16|8) x) (Com(64|32|16|8) x)) => (Const(64|32|16|8) [1])
   629  (Sub(64|32|16|8) (Com(64|32|16|8) x) (Neg(64|32|16|8) x)) => (Const(64|32|16|8) [-1])
   630  (Add(64|32|16|8) (Com(64|32|16|8) x)                  x)  => (Const(64|32|16|8) [-1])
   631  
   632  // Prove does not simplify this because x + y might overflow into carry,
   633  // however if no one care about the carry, let it overflow in a normal add.
   634  (Select0 a:(Add64carry x y (Const64 [0]))) && a.Uses == 1 => (Add64 x y)
   635  
   636  // Simplification when involving common integer
   637  // (t + x) - (t + y) == x - y
   638  // (t + x) - (y + t) == x - y
   639  // (x + t) - (y + t) == x - y
   640  // (x + t) - (t + y) == x - y
   641  // (x - t) + (t + y) == x + y
   642  // (x - t) + (y + t) == x + y
   643  (Sub(64|32|16|8) (Add(64|32|16|8) t x) (Add(64|32|16|8) t y)) => (Sub(64|32|16|8) x y)
   644  (Add(64|32|16|8) (Sub(64|32|16|8) x t) (Add(64|32|16|8) t y)) => (Add(64|32|16|8) x y)
   645  
   646  // ^(x-1) == ^x+1 == -x
   647  (Add(64|32|16|8) (Const(64|32|16|8) [1]) (Com(64|32|16|8) x)) => (Neg(64|32|16|8) x)
   648  (Com(64|32|16|8) (Add(64|32|16|8) (Const(64|32|16|8) [-1]) x)) => (Neg(64|32|16|8) x)
   649  
   650  // -(-x) == x
   651  (Neg(64|32|16|8) (Neg(64|32|16|8) x)) => x
   652  
   653  // -^x == x+1
   654  (Neg(64|32|16|8) <t> (Com(64|32|16|8) x)) => (Add(64|32|16|8) (Const(64|32|16|8) <t> [1]) x)
   655  
   656  (And(64|32|16|8) x (And(64|32|16|8) x y)) => (And(64|32|16|8) x y)
   657  (Or(64|32|16|8) x (Or(64|32|16|8) x y)) => (Or(64|32|16|8) x y)
   658  (Xor(64|32|16|8) x (Xor(64|32|16|8) x y)) => y
   659  
   660  // Fold comparisons with numeric bounds
   661  (Less(64|32|16|8)U _ (Const(64|32|16|8) [0]))  => (ConstBool [false])
   662  (Leq(64|32|16|8)U (Const(64|32|16|8) [0]) _)   => (ConstBool [true])
   663  (Less(64|32|16|8)U (Const(64|32|16|8) [-1]) _) => (ConstBool [false])
   664  (Leq(64|32|16|8)U _ (Const(64|32|16|8) [-1]))  => (ConstBool [true])
   665  (Less64 _ (Const64 [math.MinInt64])) => (ConstBool [false])
   666  (Less32 _ (Const32 [math.MinInt32])) => (ConstBool [false])
   667  (Less16 _ (Const16 [math.MinInt16])) => (ConstBool [false])
   668  (Less8  _ (Const8  [math.MinInt8 ])) => (ConstBool [false])
   669  (Leq64 (Const64 [math.MinInt64]) _)  => (ConstBool [true])
   670  (Leq32 (Const32 [math.MinInt32]) _)  => (ConstBool [true])
   671  (Leq16 (Const16 [math.MinInt16]) _)  => (ConstBool [true])
   672  (Leq8  (Const8  [math.MinInt8 ]) _)  => (ConstBool [true])
   673  (Less64 (Const64 [math.MaxInt64]) _) => (ConstBool [false])
   674  (Less32 (Const32 [math.MaxInt32]) _) => (ConstBool [false])
   675  (Less16 (Const16 [math.MaxInt16]) _) => (ConstBool [false])
   676  (Less8  (Const8  [math.MaxInt8 ]) _) => (ConstBool [false])
   677  (Leq64 _ (Const64 [math.MaxInt64]))  => (ConstBool [true])
   678  (Leq32 _ (Const32 [math.MaxInt32]))  => (ConstBool [true])
   679  (Leq16 _ (Const16 [math.MaxInt16]))  => (ConstBool [true])
   680  (Leq8  _ (Const8  [math.MaxInt8 ]))  => (ConstBool [true])
   681  
   682  // Canonicalize <= on numeric bounds and < near numeric bounds to ==
   683  (Leq(64|32|16|8)U x c:(Const(64|32|16|8) [0]))     => (Eq(64|32|16|8) x c)
   684  (Leq(64|32|16|8)U c:(Const(64|32|16|8) [-1]) x)    => (Eq(64|32|16|8) x c)
   685  (Less(64|32|16|8)U x (Const(64|32|16|8) <t> [1]))  => (Eq(64|32|16|8) x (Const(64|32|16|8) <t> [0]))
   686  (Less(64|32|16|8)U (Const(64|32|16|8) <t> [-2]) x) => (Eq(64|32|16|8) x (Const(64|32|16|8) <t> [-1]))
   687  (Leq64 x c:(Const64 [math.MinInt64])) => (Eq64 x c)
   688  (Leq32 x c:(Const32 [math.MinInt32])) => (Eq32 x c)
   689  (Leq16 x c:(Const16 [math.MinInt16])) => (Eq16 x c)
   690  (Leq8  x c:(Const8  [math.MinInt8 ])) => (Eq8  x c)
   691  (Leq64 c:(Const64 [math.MaxInt64]) x) => (Eq64 x c)
   692  (Leq32 c:(Const32 [math.MaxInt32]) x) => (Eq32 x c)
   693  (Leq16 c:(Const16 [math.MaxInt16]) x) => (Eq16 x c)
   694  (Leq8  c:(Const8  [math.MaxInt8 ]) x) => (Eq8  x c)
   695  (Less64 x (Const64 <t> [math.MinInt64+1])) => (Eq64 x (Const64 <t> [math.MinInt64]))
   696  (Less32 x (Const32 <t> [math.MinInt32+1])) => (Eq32 x (Const32 <t> [math.MinInt32]))
   697  (Less16 x (Const16 <t> [math.MinInt16+1])) => (Eq16 x (Const16 <t> [math.MinInt16]))
   698  (Less8  x (Const8  <t> [math.MinInt8 +1])) => (Eq8  x (Const8  <t> [math.MinInt8 ]))
   699  (Less64 (Const64 <t> [math.MaxInt64-1]) x) => (Eq64 x (Const64 <t> [math.MaxInt64]))
   700  (Less32 (Const32 <t> [math.MaxInt32-1]) x) => (Eq32 x (Const32 <t> [math.MaxInt32]))
   701  (Less16 (Const16 <t> [math.MaxInt16-1]) x) => (Eq16 x (Const16 <t> [math.MaxInt16]))
   702  (Less8  (Const8  <t> [math.MaxInt8 -1]) x) => (Eq8  x (Const8  <t> [math.MaxInt8 ]))
   703  
   704  // Ands clear bits. Ors set bits.
   705  // If a subsequent Or will set all the bits
   706  // that an And cleared, we can skip the And.
   707  // This happens in bitmasking code like:
   708  //   x &^= 3 << shift // clear two old bits
   709  //   x  |= v << shift // set two new bits
   710  // when shift is a small constant and v ends up a constant 3.
   711  (Or8  (And8  x (Const8  [c2])) (Const8  <t> [c1])) && ^(c1 | c2) == 0 => (Or8  (Const8  <t> [c1]) x)
   712  (Or16 (And16 x (Const16 [c2])) (Const16 <t> [c1])) && ^(c1 | c2) == 0 => (Or16 (Const16 <t> [c1]) x)
   713  (Or32 (And32 x (Const32 [c2])) (Const32 <t> [c1])) && ^(c1 | c2) == 0 => (Or32 (Const32 <t> [c1]) x)
   714  (Or64 (And64 x (Const64 [c2])) (Const64 <t> [c1])) && ^(c1 | c2) == 0 => (Or64 (Const64 <t> [c1]) x)
   715  
   716  (Trunc64to8  (And64 (Const64 [y]) x)) && y&0xFF == 0xFF => (Trunc64to8 x)
   717  (Trunc64to16 (And64 (Const64 [y]) x)) && y&0xFFFF == 0xFFFF => (Trunc64to16 x)
   718  (Trunc64to32 (And64 (Const64 [y]) x)) && y&0xFFFFFFFF == 0xFFFFFFFF => (Trunc64to32 x)
   719  (Trunc32to8  (And32 (Const32 [y]) x)) && y&0xFF == 0xFF => (Trunc32to8 x)
   720  (Trunc32to16 (And32 (Const32 [y]) x)) && y&0xFFFF == 0xFFFF => (Trunc32to16 x)
   721  (Trunc16to8  (And16 (Const16 [y]) x)) && y&0xFF == 0xFF => (Trunc16to8 x)
   722  
   723  (ZeroExt8to64  (Trunc64to8  x:(Rsh64Ux64 _ (Const64 [s])))) && s >= 56 => x
   724  (ZeroExt16to64 (Trunc64to16 x:(Rsh64Ux64 _ (Const64 [s])))) && s >= 48 => x
   725  (ZeroExt32to64 (Trunc64to32 x:(Rsh64Ux64 _ (Const64 [s])))) && s >= 32 => x
   726  (ZeroExt8to32  (Trunc32to8  x:(Rsh32Ux64 _ (Const64 [s])))) && s >= 24 => x
   727  (ZeroExt16to32 (Trunc32to16 x:(Rsh32Ux64 _ (Const64 [s])))) && s >= 16 => x
   728  (ZeroExt8to16  (Trunc16to8  x:(Rsh16Ux64 _ (Const64 [s])))) && s >= 8 => x
   729  
   730  (SignExt8to64  (Trunc64to8  x:(Rsh64x64 _ (Const64 [s])))) && s >= 56 => x
   731  (SignExt16to64 (Trunc64to16 x:(Rsh64x64 _ (Const64 [s])))) && s >= 48 => x
   732  (SignExt32to64 (Trunc64to32 x:(Rsh64x64 _ (Const64 [s])))) && s >= 32 => x
   733  (SignExt8to32  (Trunc32to8  x:(Rsh32x64 _ (Const64 [s])))) && s >= 24 => x
   734  (SignExt16to32 (Trunc32to16 x:(Rsh32x64 _ (Const64 [s])))) && s >= 16 => x
   735  (SignExt8to16  (Trunc16to8  x:(Rsh16x64 _ (Const64 [s])))) && s >= 8 => x
   736  
   737  (Slicemask (Const32 [x])) && x > 0 => (Const32 [-1])
   738  (Slicemask (Const32 [0]))          => (Const32 [0])
   739  (Slicemask (Const64 [x])) && x > 0 => (Const64 [-1])
   740  (Slicemask (Const64 [0]))          => (Const64 [0])
   741  
   742  // simplifications often used for lengths.  e.g. len(s[i:i+5])==5
   743  (Sub(64|32|16|8) (Add(64|32|16|8) x y) x) => y
   744  (Sub(64|32|16|8) (Add(64|32|16|8) x y) y) => x
   745  (Sub(64|32|16|8) (Sub(64|32|16|8) x y) x) => (Neg(64|32|16|8) y)
   746  (Sub(64|32|16|8) x (Add(64|32|16|8) x y)) => (Neg(64|32|16|8) y)
   747  (Add(64|32|16|8) x (Sub(64|32|16|8) y x)) => y
   748  (Add(64|32|16|8) x (Add(64|32|16|8) y (Sub(64|32|16|8) z x))) => (Add(64|32|16|8) y z)
   749  
   750  // basic phi simplifications
   751  (Phi (Const8  [c]) (Const8  [c])) => (Const8  [c])
   752  (Phi (Const16 [c]) (Const16 [c])) => (Const16 [c])
   753  (Phi (Const32 [c]) (Const32 [c])) => (Const32 [c])
   754  (Phi (Const64 [c]) (Const64 [c])) => (Const64 [c])
   755  
   756  // slice and interface comparisons
   757  // The frontend ensures that we can only compare against nil,
   758  // so we need only compare the first word (interface type or slice ptr).
   759  (EqInter x y)  => (EqPtr  (ITab x) (ITab y))
   760  (NeqInter x y) => (NeqPtr (ITab x) (ITab y))
   761  (EqSlice x y)  => (EqPtr  (SlicePtr x) (SlicePtr y))
   762  (NeqSlice x y) => (NeqPtr (SlicePtr x) (SlicePtr y))
   763  
   764  // Load of store of same address, with compatibly typed value and same size
   765  (Load <t1> p1 (Store {t2} p2 x _))
   766  	&& isSamePtr(p1, p2)
   767  	&& copyCompatibleType(t1, x.Type)
   768  	&& t1.Size() == t2.Size()
   769  	=> x
   770  (Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 x _)))
   771  	&& isSamePtr(p1, p3)
   772  	&& copyCompatibleType(t1, x.Type)
   773  	&& t1.Size() == t3.Size()
   774  	&& disjoint(p3, t3.Size(), p2, t2.Size())
   775  	=> x
   776  (Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 x _))))
   777  	&& isSamePtr(p1, p4)
   778  	&& copyCompatibleType(t1, x.Type)
   779  	&& t1.Size() == t4.Size()
   780  	&& disjoint(p4, t4.Size(), p2, t2.Size())
   781  	&& disjoint(p4, t4.Size(), p3, t3.Size())
   782  	=> x
   783  (Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 _ (Store {t5} p5 x _)))))
   784  	&& isSamePtr(p1, p5)
   785  	&& copyCompatibleType(t1, x.Type)
   786  	&& t1.Size() == t5.Size()
   787  	&& disjoint(p5, t5.Size(), p2, t2.Size())
   788  	&& disjoint(p5, t5.Size(), p3, t3.Size())
   789  	&& disjoint(p5, t5.Size(), p4, t4.Size())
   790  	=> x
   791  
   792  // Pass constants through math.Float{32,64}bits and math.Float{32,64}frombits
   793  (Load <t1> p1 (Store {t2} p2 (Const64  [x]) _)) && isSamePtr(p1,p2) && t2.Size() == 8 && is64BitFloat(t1) && !math.IsNaN(math.Float64frombits(uint64(x))) => (Const64F [math.Float64frombits(uint64(x))])
   794  (Load <t1> p1 (Store {t2} p2 (Const32  [x]) _)) && isSamePtr(p1,p2) && t2.Size() == 4 && is32BitFloat(t1) && !math.IsNaN(float64(math.Float32frombits(uint32(x)))) => (Const32F [math.Float32frombits(uint32(x))])
   795  (Load <t1> p1 (Store {t2} p2 (Const64F [x]) _)) && isSamePtr(p1,p2) && t2.Size() == 8 && is64BitInt(t1)   => (Const64  [int64(math.Float64bits(x))])
   796  (Load <t1> p1 (Store {t2} p2 (Const32F [x]) _)) && isSamePtr(p1,p2) && t2.Size() == 4 && is32BitInt(t1)   => (Const32  [int32(math.Float32bits(x))])
   797  
   798  // Float Loads up to Zeros so they can be constant folded.
   799  (Load <t1> op:(OffPtr [o1] p1)
   800  	(Store {t2} p2 _
   801  		mem:(Zero [n] p3 _)))
   802  	&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p3)
   803  	&& CanSSA(t1)
   804  	&& disjoint(op, t1.Size(), p2, t2.Size())
   805  	=> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p3) mem)
   806  (Load <t1> op:(OffPtr [o1] p1)
   807  	(Store {t2} p2 _
   808  		(Store {t3} p3 _
   809  			mem:(Zero [n] p4 _))))
   810  	&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p4)
   811  	&& CanSSA(t1)
   812  	&& disjoint(op, t1.Size(), p2, t2.Size())
   813  	&& disjoint(op, t1.Size(), p3, t3.Size())
   814  	=> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p4) mem)
   815  (Load <t1> op:(OffPtr [o1] p1)
   816  	(Store {t2} p2 _
   817  		(Store {t3} p3 _
   818  			(Store {t4} p4 _
   819  				mem:(Zero [n] p5 _)))))
   820  	&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p5)
   821  	&& CanSSA(t1)
   822  	&& disjoint(op, t1.Size(), p2, t2.Size())
   823  	&& disjoint(op, t1.Size(), p3, t3.Size())
   824  	&& disjoint(op, t1.Size(), p4, t4.Size())
   825  	=> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p5) mem)
   826  (Load <t1> op:(OffPtr [o1] p1)
   827  	(Store {t2} p2 _
   828  		(Store {t3} p3 _
   829  			(Store {t4} p4 _
   830  				(Store {t5} p5 _
   831  					mem:(Zero [n] p6 _))))))
   832  	&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p6)
   833  	&& CanSSA(t1)
   834  	&& disjoint(op, t1.Size(), p2, t2.Size())
   835  	&& disjoint(op, t1.Size(), p3, t3.Size())
   836  	&& disjoint(op, t1.Size(), p4, t4.Size())
   837  	&& disjoint(op, t1.Size(), p5, t5.Size())
   838  	=> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p6) mem)
   839  
   840  // Zero to Load forwarding.
   841  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   842  	&& t1.IsBoolean()
   843  	&& isSamePtr(p1, p2)
   844  	&& n >= o + 1
   845  	=> (ConstBool [false])
   846  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   847  	&& is8BitInt(t1)
   848  	&& isSamePtr(p1, p2)
   849  	&& n >= o + 1
   850  	=> (Const8 [0])
   851  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   852  	&& is16BitInt(t1)
   853  	&& isSamePtr(p1, p2)
   854  	&& n >= o + 2
   855  	=> (Const16 [0])
   856  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   857  	&& is32BitInt(t1)
   858  	&& isSamePtr(p1, p2)
   859  	&& n >= o + 4
   860  	=> (Const32 [0])
   861  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   862  	&& is64BitInt(t1)
   863  	&& isSamePtr(p1, p2)
   864  	&& n >= o + 8
   865  	=> (Const64 [0])
   866  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   867  	&& is32BitFloat(t1)
   868  	&& isSamePtr(p1, p2)
   869  	&& n >= o + 4
   870  	=> (Const32F [0])
   871  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   872  	&& is64BitFloat(t1)
   873  	&& isSamePtr(p1, p2)
   874  	&& n >= o + 8
   875  	=> (Const64F [0])
   876  
   877  // Eliminate stores of values that have just been loaded from the same location.
   878  // We also handle the common case where there are some intermediate stores.
   879  (Store {t1} p1 (Load <t2> p2 mem) mem)
   880  	&& isSamePtr(p1, p2)
   881  	&& t2.Size() == t1.Size()
   882  	=> mem
   883  (Store {t1} p1 (Load <t2> p2 oldmem) mem:(Store {t3} p3 _ oldmem))
   884  	&& isSamePtr(p1, p2)
   885  	&& t2.Size() == t1.Size()
   886  	&& disjoint(p1, t1.Size(), p3, t3.Size())
   887  	=> mem
   888  (Store {t1} p1 (Load <t2> p2 oldmem) mem:(Store {t3} p3 _ (Store {t4} p4 _ oldmem)))
   889  	&& isSamePtr(p1, p2)
   890  	&& t2.Size() == t1.Size()
   891  	&& disjoint(p1, t1.Size(), p3, t3.Size())
   892  	&& disjoint(p1, t1.Size(), p4, t4.Size())
   893  	=> mem
   894  (Store {t1} p1 (Load <t2> p2 oldmem) mem:(Store {t3} p3 _ (Store {t4} p4 _ (Store {t5} p5 _ oldmem))))
   895  	&& isSamePtr(p1, p2)
   896  	&& t2.Size() == t1.Size()
   897  	&& disjoint(p1, t1.Size(), p3, t3.Size())
   898  	&& disjoint(p1, t1.Size(), p4, t4.Size())
   899  	&& disjoint(p1, t1.Size(), p5, t5.Size())
   900  	=> mem
   901  
   902  // Don't Store zeros to cleared variables.
   903  (Store {t} (OffPtr [o] p1) x mem:(Zero [n] p2 _))
   904  	&& isConstZero(x)
   905  	&& o >= 0 && t.Size() + o <= n && isSamePtr(p1, p2)
   906  	=> mem
   907  (Store {t1} op:(OffPtr [o1] p1) x mem:(Store {t2} p2 _ (Zero [n] p3 _)))
   908  	&& isConstZero(x)
   909  	&& o1 >= 0 && t1.Size() + o1 <= n && isSamePtr(p1, p3)
   910  	&& disjoint(op, t1.Size(), p2, t2.Size())
   911  	=> mem
   912  (Store {t1} op:(OffPtr [o1] p1) x mem:(Store {t2} p2 _ (Store {t3} p3 _ (Zero [n] p4 _))))
   913  	&& isConstZero(x)
   914  	&& o1 >= 0 && t1.Size() + o1 <= n && isSamePtr(p1, p4)
   915  	&& disjoint(op, t1.Size(), p2, t2.Size())
   916  	&& disjoint(op, t1.Size(), p3, t3.Size())
   917  	=> mem
   918  (Store {t1} op:(OffPtr [o1] p1) x mem:(Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 _ (Zero [n] p5 _)))))
   919  	&& isConstZero(x)
   920  	&& o1 >= 0 && t1.Size() + o1 <= n && isSamePtr(p1, p5)
   921  	&& disjoint(op, t1.Size(), p2, t2.Size())
   922  	&& disjoint(op, t1.Size(), p3, t3.Size())
   923  	&& disjoint(op, t1.Size(), p4, t4.Size())
   924  	=> mem
   925  
   926  // Collapse OffPtr
   927  (OffPtr (OffPtr p [y]) [x]) => (OffPtr p [x+y])
   928  (OffPtr p [0]) && v.Type.Compare(p.Type) == types.CMPeq => p
   929  
   930  // indexing operations
   931  // Note: bounds check has already been done
   932  (PtrIndex <t> ptr idx) && config.PtrSize == 4 && is32Bit(t.Elem().Size()) => (AddPtr ptr (Mul32 <typ.Int> idx (Const32 <typ.Int> [int32(t.Elem().Size())])))
   933  (PtrIndex <t> ptr idx) && config.PtrSize == 8 => (AddPtr ptr (Mul64 <typ.Int> idx (Const64 <typ.Int> [t.Elem().Size()])))
   934  
   935  // struct operations
   936  (StructSelect [i] x:(StructMake ___)) => x.Args[i]
   937  (Load <t> _ _) && t.IsStruct() && CanSSA(t) => rewriteStructLoad(v)
   938  (Store _ (StructMake ___) _) => rewriteStructStore(v)
   939  
   940  (StructSelect [i] x:(Load <t> ptr mem)) && !CanSSA(t) =>
   941    @x.Block (Load <v.Type> (OffPtr <v.Type.PtrTo()> [t.FieldOff(int(i))] ptr) mem)
   942  
   943  // Putting struct{*byte} and similar into direct interfaces.
   944  (IMake _typ (StructMake val)) => (IMake _typ val)
   945  (StructSelect [0] (IData x)) => (IData x)
   946  
   947  // un-SSAable values use mem->mem copies
   948  (Store {t} dst (Load src mem) mem) && !CanSSA(t) =>
   949  	(Move {t} [t.Size()] dst src mem)
   950  (Store {t} dst (Load src mem) (VarDef {x} mem)) && !CanSSA(t) =>
   951  	(Move {t} [t.Size()] dst src (VarDef {x} mem))
   952  
   953  // array ops
   954  (ArraySelect (ArrayMake1 x)) => x
   955  
   956  (Load <t> _ _) && t.IsArray() && t.NumElem() == 0 =>
   957    (ArrayMake0)
   958  
   959  (Load <t> ptr mem) && t.IsArray() && t.NumElem() == 1 && CanSSA(t) =>
   960    (ArrayMake1 (Load <t.Elem()> ptr mem))
   961  
   962  (Store _ (ArrayMake0) mem) => mem
   963  (Store dst (ArrayMake1 e) mem) => (Store {e.Type} dst e mem)
   964  
   965  // Putting [1]*byte and similar into direct interfaces.
   966  (IMake _typ (ArrayMake1 val)) => (IMake _typ val)
   967  (ArraySelect [0] (IData x)) => (IData x)
   968  
   969  // string ops
   970  // Decomposing StringMake and lowering of StringPtr and StringLen
   971  // happens in a later pass, dec, so that these operations are available
   972  // to other passes for optimizations.
   973  (StringPtr (StringMake (Addr <t> {s} base) _)) => (Addr <t> {s} base)
   974  (StringLen (StringMake _ (Const64 <t> [c]))) => (Const64 <t> [c])
   975  (ConstString {str}) && config.PtrSize == 4 && str == "" =>
   976    (StringMake (ConstNil) (Const32 <typ.Int> [0]))
   977  (ConstString {str}) && config.PtrSize == 8 && str == "" =>
   978    (StringMake (ConstNil) (Const64 <typ.Int> [0]))
   979  (ConstString {str}) && config.PtrSize == 4 && str != "" =>
   980    (StringMake
   981      (Addr <typ.BytePtr> {fe.StringData(str)}
   982        (SB))
   983      (Const32 <typ.Int> [int32(len(str))]))
   984  (ConstString {str}) && config.PtrSize == 8 && str != "" =>
   985    (StringMake
   986      (Addr <typ.BytePtr> {fe.StringData(str)}
   987        (SB))
   988      (Const64 <typ.Int> [int64(len(str))]))
   989  
   990  // slice ops
   991  // Only a few slice rules are provided here.  See dec.rules for
   992  // a more comprehensive set.
   993  (SliceLen (SliceMake _ (Const64 <t> [c]) _)) => (Const64 <t> [c])
   994  (SliceCap (SliceMake _ _ (Const64 <t> [c]))) => (Const64 <t> [c])
   995  (SliceLen (SliceMake _ (Const32 <t> [c]) _)) => (Const32 <t> [c])
   996  (SliceCap (SliceMake _ _ (Const32 <t> [c]))) => (Const32 <t> [c])
   997  (SlicePtr (SliceMake (SlicePtr x) _ _)) => (SlicePtr x)
   998  (SliceLen (SliceMake _ (SliceLen x) _)) => (SliceLen x)
   999  (SliceCap (SliceMake _ _ (SliceCap x))) => (SliceCap x)
  1000  (SliceCap (SliceMake _ _ (SliceLen x))) => (SliceLen x)
  1001  (ConstSlice) && config.PtrSize == 4 =>
  1002    (SliceMake
  1003      (ConstNil <v.Type.Elem().PtrTo()>)
  1004      (Const32 <typ.Int> [0])
  1005      (Const32 <typ.Int> [0]))
  1006  (ConstSlice) && config.PtrSize == 8 =>
  1007    (SliceMake
  1008      (ConstNil <v.Type.Elem().PtrTo()>)
  1009      (Const64 <typ.Int> [0])
  1010      (Const64 <typ.Int> [0]))
  1011  
  1012  // Special rule to help constant slicing; len > 0 implies cap > 0 implies Slicemask is all 1
  1013  (SliceMake (AddPtr <t> x (And64 y (Slicemask _))) w:(Const64 [c]) z) && c > 0 => (SliceMake (AddPtr <t> x y) w z)
  1014  (SliceMake (AddPtr <t> x (And32 y (Slicemask _))) w:(Const32 [c]) z) && c > 0 => (SliceMake (AddPtr <t> x y) w z)
  1015  
  1016  // interface ops
  1017  (ConstInterface) =>
  1018    (IMake
  1019      (ConstNil <typ.Uintptr>)
  1020      (ConstNil <typ.BytePtr>))
  1021  
  1022  (NilCheck ptr:(GetG mem) mem) => ptr
  1023  
  1024  (If (Not cond) yes no) => (If cond no yes)
  1025  (If (ConstBool [c]) yes no) && c => (First yes no)
  1026  (If (ConstBool [c]) yes no) && !c => (First no yes)
  1027  
  1028  (Phi <t> nx:(Not x) ny:(Not y)) && nx.Uses == 1 && ny.Uses == 1 => (Not (Phi <t> x y))
  1029  
  1030  // Get rid of Convert ops for pointer arithmetic on unsafe.Pointer.
  1031  (Convert (Add(64|32) (Convert ptr mem) off) mem) => (AddPtr ptr off)
  1032  (Convert (Convert ptr mem) mem) => ptr
  1033  // Note: it is important that the target rewrite is ptr+(off1+off2), not (ptr+off1)+off2.
  1034  // We must ensure that no intermediate computations are invalid pointers.
  1035  (Convert a:(Add(64|32) (Add(64|32) (Convert ptr mem) off1) off2) mem) => (AddPtr ptr (Add(64|32) <a.Type> off1 off2))
  1036  
  1037  // strength reduction of divide by a constant.
  1038  // See ../magic.go for a detailed description of these algorithms.
  1039  
  1040  // Unsigned divide by power of 2.  Strength reduce to a shift.
  1041  (Div8u  n (Const8  [c])) && isUnsignedPowerOfTwo(uint8(c)) => (Rsh8Ux64  n (Const64 <typ.UInt64> [log8u(uint8(c))]))
  1042  (Div16u n (Const16 [c])) && isUnsignedPowerOfTwo(uint16(c)) => (Rsh16Ux64 n (Const64 <typ.UInt64> [log16u(uint16(c))]))
  1043  (Div32u n (Const32 [c])) && isUnsignedPowerOfTwo(uint32(c)) => (Rsh32Ux64 n (Const64 <typ.UInt64> [log32u(uint32(c))]))
  1044  (Div64u n (Const64 [c])) && isUnsignedPowerOfTwo(uint64(c)) => (Rsh64Ux64 n (Const64 <typ.UInt64> [log64u(uint64(c))]))
  1045  
  1046  // Signed non-negative divide by power of 2.
  1047  (Div8  n (Const8  [c])) && isNonNegative(n) && isPowerOfTwo(c) => (Rsh8Ux64  n (Const64 <typ.UInt64> [log8(c)]))
  1048  (Div16 n (Const16 [c])) && isNonNegative(n) && isPowerOfTwo(c) => (Rsh16Ux64 n (Const64 <typ.UInt64> [log16(c)]))
  1049  (Div32 n (Const32 [c])) && isNonNegative(n) && isPowerOfTwo(c) => (Rsh32Ux64 n (Const64 <typ.UInt64> [log32(c)]))
  1050  (Div64 n (Const64 [c])) && isNonNegative(n) && isPowerOfTwo(c) => (Rsh64Ux64 n (Const64 <typ.UInt64> [log64(c)]))
  1051  (Div64 n (Const64 [-1<<63])) && isNonNegative(n)                 => (Const64 [0])
  1052  
  1053  // Unsigned divide, not a power of 2.  Strength reduce to a multiply.
  1054  // For 8-bit divides, we just do a direct 9-bit by 8-bit multiply.
  1055  (Div8u x (Const8 [c])) && umagicOK8(c) =>
  1056    (Trunc32to8
  1057      (Rsh32Ux64 <typ.UInt32>
  1058        (Mul32 <typ.UInt32>
  1059          (Const32 <typ.UInt32> [int32(1<<8+umagic8(c).m)])
  1060          (ZeroExt8to32 x))
  1061        (Const64 <typ.UInt64> [8+umagic8(c).s])))
  1062  
  1063  // For 16-bit divides on 64-bit machines, we do a direct 17-bit by 16-bit multiply.
  1064  (Div16u x (Const16 [c])) && umagicOK16(c) && config.RegSize == 8 =>
  1065    (Trunc64to16
  1066      (Rsh64Ux64 <typ.UInt64>
  1067        (Mul64 <typ.UInt64>
  1068          (Const64 <typ.UInt64> [int64(1<<16+umagic16(c).m)])
  1069          (ZeroExt16to64 x))
  1070        (Const64 <typ.UInt64> [16+umagic16(c).s])))
  1071  
  1072  // For 16-bit divides on 32-bit machines
  1073  (Div16u x (Const16 [c])) && umagicOK16(c) && config.RegSize == 4 && umagic16(c).m&1 == 0 =>
  1074    (Trunc32to16
  1075      (Rsh32Ux64 <typ.UInt32>
  1076        (Mul32 <typ.UInt32>
  1077          (Const32 <typ.UInt32> [int32(1<<15+umagic16(c).m/2)])
  1078          (ZeroExt16to32 x))
  1079        (Const64 <typ.UInt64> [16+umagic16(c).s-1])))
  1080  (Div16u x (Const16 [c])) && umagicOK16(c) && config.RegSize == 4 && c&1 == 0 =>
  1081    (Trunc32to16
  1082      (Rsh32Ux64 <typ.UInt32>
  1083        (Mul32 <typ.UInt32>
  1084          (Const32 <typ.UInt32> [int32(1<<15+(umagic16(c).m+1)/2)])
  1085          (Rsh32Ux64 <typ.UInt32> (ZeroExt16to32 x) (Const64 <typ.UInt64> [1])))
  1086        (Const64 <typ.UInt64> [16+umagic16(c).s-2])))
  1087  (Div16u x (Const16 [c])) && umagicOK16(c) && config.RegSize == 4 && config.useAvg =>
  1088    (Trunc32to16
  1089      (Rsh32Ux64 <typ.UInt32>
  1090        (Avg32u
  1091          (Lsh32x64 <typ.UInt32> (ZeroExt16to32 x) (Const64 <typ.UInt64> [16]))
  1092          (Mul32 <typ.UInt32>
  1093            (Const32 <typ.UInt32> [int32(umagic16(c).m)])
  1094            (ZeroExt16to32 x)))
  1095        (Const64 <typ.UInt64> [16+umagic16(c).s-1])))
  1096  
  1097  // For 32-bit divides on 32-bit machines
  1098  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 4 && umagic32(c).m&1 == 0 && config.useHmul =>
  1099    (Rsh32Ux64 <typ.UInt32>
  1100      (Hmul32u <typ.UInt32>
  1101        (Const32 <typ.UInt32> [int32(1<<31+umagic32(c).m/2)])
  1102        x)
  1103      (Const64 <typ.UInt64> [umagic32(c).s-1]))
  1104  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 4 && c&1 == 0 && config.useHmul =>
  1105    (Rsh32Ux64 <typ.UInt32>
  1106      (Hmul32u <typ.UInt32>
  1107        (Const32 <typ.UInt32> [int32(1<<31+(umagic32(c).m+1)/2)])
  1108        (Rsh32Ux64 <typ.UInt32> x (Const64 <typ.UInt64> [1])))
  1109      (Const64 <typ.UInt64> [umagic32(c).s-2]))
  1110  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 4 && config.useAvg && config.useHmul =>
  1111    (Rsh32Ux64 <typ.UInt32>
  1112      (Avg32u
  1113        x
  1114        (Hmul32u <typ.UInt32>
  1115          (Const32 <typ.UInt32> [int32(umagic32(c).m)])
  1116          x))
  1117      (Const64 <typ.UInt64> [umagic32(c).s-1]))
  1118  
  1119  // For 32-bit divides on 64-bit machines
  1120  // We'll use a regular (non-hi) multiply for this case.
  1121  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 8 && umagic32(c).m&1 == 0 =>
  1122    (Trunc64to32
  1123      (Rsh64Ux64 <typ.UInt64>
  1124        (Mul64 <typ.UInt64>
  1125          (Const64 <typ.UInt64> [int64(1<<31+umagic32(c).m/2)])
  1126          (ZeroExt32to64 x))
  1127        (Const64 <typ.UInt64> [32+umagic32(c).s-1])))
  1128  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 8 && c&1 == 0 =>
  1129    (Trunc64to32
  1130      (Rsh64Ux64 <typ.UInt64>
  1131        (Mul64 <typ.UInt64>
  1132          (Const64 <typ.UInt64> [int64(1<<31+(umagic32(c).m+1)/2)])
  1133          (Rsh64Ux64 <typ.UInt64> (ZeroExt32to64 x) (Const64 <typ.UInt64> [1])))
  1134        (Const64 <typ.UInt64> [32+umagic32(c).s-2])))
  1135  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 8 && config.useAvg =>
  1136    (Trunc64to32
  1137      (Rsh64Ux64 <typ.UInt64>
  1138        (Avg64u
  1139          (Lsh64x64 <typ.UInt64> (ZeroExt32to64 x) (Const64 <typ.UInt64> [32]))
  1140          (Mul64 <typ.UInt64>
  1141            (Const64 <typ.UInt32> [int64(umagic32(c).m)])
  1142            (ZeroExt32to64 x)))
  1143        (Const64 <typ.UInt64> [32+umagic32(c).s-1])))
  1144  
  1145  // For unsigned 64-bit divides on 32-bit machines,
  1146  // if the constant fits in 16 bits (so that the last term
  1147  // fits in 32 bits), convert to three 32-bit divides by a constant.
  1148  //
  1149  // If 1<<32 = Q * c + R
  1150  // and    x = hi << 32 + lo
  1151  //
  1152  // Then x = (hi/c*c + hi%c) << 32 + lo
  1153  //        = hi/c*c<<32 + hi%c<<32 + lo
  1154  //        = hi/c*c<<32 + (hi%c)*(Q*c+R) + lo/c*c + lo%c
  1155  //        = hi/c*c<<32 + (hi%c)*Q*c + lo/c*c + (hi%c*R+lo%c)
  1156  // and x / c = (hi/c)<<32 + (hi%c)*Q + lo/c + (hi%c*R+lo%c)/c
  1157  (Div64u x (Const64 [c])) && c > 0 && c <= 0xFFFF && umagicOK32(int32(c)) && config.RegSize == 4 && config.useHmul =>
  1158    (Add64
  1159      (Add64 <typ.UInt64>
  1160        (Add64 <typ.UInt64>
  1161          (Lsh64x64 <typ.UInt64>
  1162            (ZeroExt32to64
  1163              (Div32u <typ.UInt32>
  1164                (Trunc64to32 <typ.UInt32> (Rsh64Ux64 <typ.UInt64> x (Const64 <typ.UInt64> [32])))
  1165                (Const32 <typ.UInt32> [int32(c)])))
  1166            (Const64 <typ.UInt64> [32]))
  1167          (ZeroExt32to64 (Div32u <typ.UInt32> (Trunc64to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(c)]))))
  1168        (Mul64 <typ.UInt64>
  1169          (ZeroExt32to64 <typ.UInt64>
  1170            (Mod32u <typ.UInt32>
  1171              (Trunc64to32 <typ.UInt32> (Rsh64Ux64 <typ.UInt64> x (Const64 <typ.UInt64> [32])))
  1172              (Const32 <typ.UInt32> [int32(c)])))
  1173          (Const64 <typ.UInt64> [int64((1<<32)/c)])))
  1174        (ZeroExt32to64
  1175          (Div32u <typ.UInt32>
  1176            (Add32 <typ.UInt32>
  1177              (Mod32u <typ.UInt32> (Trunc64to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(c)]))
  1178              (Mul32 <typ.UInt32>
  1179                (Mod32u <typ.UInt32>
  1180                  (Trunc64to32 <typ.UInt32> (Rsh64Ux64 <typ.UInt64> x (Const64 <typ.UInt64> [32])))
  1181                  (Const32 <typ.UInt32> [int32(c)]))
  1182                (Const32 <typ.UInt32> [int32((1<<32)%c)])))
  1183            (Const32 <typ.UInt32> [int32(c)]))))
  1184  
  1185  // For 64-bit divides on 64-bit machines
  1186  // (64-bit divides on 32-bit machines are lowered to a runtime call by the walk pass.)
  1187  (Div64u x (Const64 [c])) && umagicOK64(c) && config.RegSize == 8 && umagic64(c).m&1 == 0 && config.useHmul =>
  1188    (Rsh64Ux64 <typ.UInt64>
  1189      (Hmul64u <typ.UInt64>
  1190        (Const64 <typ.UInt64> [int64(1<<63+umagic64(c).m/2)])
  1191        x)
  1192      (Const64 <typ.UInt64> [umagic64(c).s-1]))
  1193  (Div64u x (Const64 [c])) && umagicOK64(c) && config.RegSize == 8 && c&1 == 0 && config.useHmul =>
  1194    (Rsh64Ux64 <typ.UInt64>
  1195      (Hmul64u <typ.UInt64>
  1196        (Const64 <typ.UInt64> [int64(1<<63+(umagic64(c).m+1)/2)])
  1197        (Rsh64Ux64 <typ.UInt64> x (Const64 <typ.UInt64> [1])))
  1198      (Const64 <typ.UInt64> [umagic64(c).s-2]))
  1199  (Div64u x (Const64 [c])) && umagicOK64(c) && config.RegSize == 8 && config.useAvg && config.useHmul =>
  1200    (Rsh64Ux64 <typ.UInt64>
  1201      (Avg64u
  1202        x
  1203        (Hmul64u <typ.UInt64>
  1204          (Const64 <typ.UInt64> [int64(umagic64(c).m)])
  1205          x))
  1206      (Const64 <typ.UInt64> [umagic64(c).s-1]))
  1207  
  1208  // Signed divide by a negative constant.  Rewrite to divide by a positive constant.
  1209  (Div8  <t> n (Const8  [c])) && c < 0 && c != -1<<7  => (Neg8  (Div8  <t> n (Const8  <t> [-c])))
  1210  (Div16 <t> n (Const16 [c])) && c < 0 && c != -1<<15 => (Neg16 (Div16 <t> n (Const16 <t> [-c])))
  1211  (Div32 <t> n (Const32 [c])) && c < 0 && c != -1<<31 => (Neg32 (Div32 <t> n (Const32 <t> [-c])))
  1212  (Div64 <t> n (Const64 [c])) && c < 0 && c != -1<<63 => (Neg64 (Div64 <t> n (Const64 <t> [-c])))
  1213  
  1214  // Dividing by the most-negative number.  Result is always 0 except
  1215  // if the input is also the most-negative number.
  1216  // We can detect that using the sign bit of x & -x.
  1217  (Div8  <t> x (Const8  [-1<<7 ])) => (Rsh8Ux64  (And8  <t> x (Neg8  <t> x)) (Const64 <typ.UInt64> [7 ]))
  1218  (Div16 <t> x (Const16 [-1<<15])) => (Rsh16Ux64 (And16 <t> x (Neg16 <t> x)) (Const64 <typ.UInt64> [15]))
  1219  (Div32 <t> x (Const32 [-1<<31])) => (Rsh32Ux64 (And32 <t> x (Neg32 <t> x)) (Const64 <typ.UInt64> [31]))
  1220  (Div64 <t> x (Const64 [-1<<63])) => (Rsh64Ux64 (And64 <t> x (Neg64 <t> x)) (Const64 <typ.UInt64> [63]))
  1221  
  1222  // Signed divide by power of 2.
  1223  // n / c =       n >> log(c) if n >= 0
  1224  //       = (n+c-1) >> log(c) if n < 0
  1225  // We conditionally add c-1 by adding n>>63>>(64-log(c)) (first shift signed, second shift unsigned).
  1226  (Div8  <t> n (Const8  [c])) && isPowerOfTwo(c) =>
  1227    (Rsh8x64
  1228      (Add8  <t> n (Rsh8Ux64  <t> (Rsh8x64  <t> n (Const64 <typ.UInt64> [ 7])) (Const64 <typ.UInt64> [int64( 8-log8(c))])))
  1229      (Const64 <typ.UInt64> [int64(log8(c))]))
  1230  (Div16 <t> n (Const16 [c])) && isPowerOfTwo(c) =>
  1231    (Rsh16x64
  1232      (Add16 <t> n (Rsh16Ux64 <t> (Rsh16x64 <t> n (Const64 <typ.UInt64> [15])) (Const64 <typ.UInt64> [int64(16-log16(c))])))
  1233      (Const64 <typ.UInt64> [int64(log16(c))]))
  1234  (Div32 <t> n (Const32 [c])) && isPowerOfTwo(c) =>
  1235    (Rsh32x64
  1236      (Add32 <t> n (Rsh32Ux64 <t> (Rsh32x64 <t> n (Const64 <typ.UInt64> [31])) (Const64 <typ.UInt64> [int64(32-log32(c))])))
  1237      (Const64 <typ.UInt64> [int64(log32(c))]))
  1238  (Div64 <t> n (Const64 [c])) && isPowerOfTwo(c) =>
  1239    (Rsh64x64
  1240      (Add64 <t> n (Rsh64Ux64 <t> (Rsh64x64 <t> n (Const64 <typ.UInt64> [63])) (Const64 <typ.UInt64> [int64(64-log64(c))])))
  1241      (Const64 <typ.UInt64> [int64(log64(c))]))
  1242  
  1243  // Signed divide, not a power of 2.  Strength reduce to a multiply.
  1244  (Div8 <t> x (Const8 [c])) && smagicOK8(c) =>
  1245    (Sub8 <t>
  1246      (Rsh32x64 <t>
  1247        (Mul32 <typ.UInt32>
  1248          (Const32 <typ.UInt32> [int32(smagic8(c).m)])
  1249          (SignExt8to32 x))
  1250        (Const64 <typ.UInt64> [8+smagic8(c).s]))
  1251      (Rsh32x64 <t>
  1252        (SignExt8to32 x)
  1253        (Const64 <typ.UInt64> [31])))
  1254  (Div16 <t> x (Const16 [c])) && smagicOK16(c) =>
  1255    (Sub16 <t>
  1256      (Rsh32x64 <t>
  1257        (Mul32 <typ.UInt32>
  1258          (Const32 <typ.UInt32> [int32(smagic16(c).m)])
  1259          (SignExt16to32 x))
  1260        (Const64 <typ.UInt64> [16+smagic16(c).s]))
  1261      (Rsh32x64 <t>
  1262        (SignExt16to32 x)
  1263        (Const64 <typ.UInt64> [31])))
  1264  (Div32 <t> x (Const32 [c])) && smagicOK32(c) && config.RegSize == 8 =>
  1265    (Sub32 <t>
  1266      (Rsh64x64 <t>
  1267        (Mul64 <typ.UInt64>
  1268          (Const64 <typ.UInt64> [int64(smagic32(c).m)])
  1269          (SignExt32to64 x))
  1270        (Const64 <typ.UInt64> [32+smagic32(c).s]))
  1271      (Rsh64x64 <t>
  1272        (SignExt32to64 x)
  1273        (Const64 <typ.UInt64> [63])))
  1274  (Div32 <t> x (Const32 [c])) && smagicOK32(c) && config.RegSize == 4 && smagic32(c).m&1 == 0 && config.useHmul =>
  1275    (Sub32 <t>
  1276      (Rsh32x64 <t>
  1277        (Hmul32 <t>
  1278          (Const32 <typ.UInt32> [int32(smagic32(c).m/2)])
  1279          x)
  1280        (Const64 <typ.UInt64> [smagic32(c).s-1]))
  1281      (Rsh32x64 <t>
  1282        x
  1283        (Const64 <typ.UInt64> [31])))
  1284  (Div32 <t> x (Const32 [c])) && smagicOK32(c) && config.RegSize == 4 && smagic32(c).m&1 != 0 && config.useHmul =>
  1285    (Sub32 <t>
  1286      (Rsh32x64 <t>
  1287        (Add32 <t>
  1288          (Hmul32 <t>
  1289            (Const32 <typ.UInt32> [int32(smagic32(c).m)])
  1290            x)
  1291          x)
  1292        (Const64 <typ.UInt64> [smagic32(c).s]))
  1293      (Rsh32x64 <t>
  1294        x
  1295        (Const64 <typ.UInt64> [31])))
  1296  (Div64 <t> x (Const64 [c])) && smagicOK64(c) && smagic64(c).m&1 == 0 && config.useHmul =>
  1297    (Sub64 <t>
  1298      (Rsh64x64 <t>
  1299        (Hmul64 <t>
  1300          (Const64 <typ.UInt64> [int64(smagic64(c).m/2)])
  1301          x)
  1302        (Const64 <typ.UInt64> [smagic64(c).s-1]))
  1303      (Rsh64x64 <t>
  1304        x
  1305        (Const64 <typ.UInt64> [63])))
  1306  (Div64 <t> x (Const64 [c])) && smagicOK64(c) && smagic64(c).m&1 != 0 && config.useHmul =>
  1307    (Sub64 <t>
  1308      (Rsh64x64 <t>
  1309        (Add64 <t>
  1310          (Hmul64 <t>
  1311            (Const64 <typ.UInt64> [int64(smagic64(c).m)])
  1312            x)
  1313          x)
  1314        (Const64 <typ.UInt64> [smagic64(c).s]))
  1315      (Rsh64x64 <t>
  1316        x
  1317        (Const64 <typ.UInt64> [63])))
  1318  
  1319  // Unsigned mod by power of 2 constant.
  1320  (Mod8u  <t> n (Const8  [c])) && isUnsignedPowerOfTwo(uint8(c)) => (And8  n (Const8  <t> [c-1]))
  1321  (Mod16u <t> n (Const16 [c])) && isUnsignedPowerOfTwo(uint16(c)) => (And16 n (Const16 <t> [c-1]))
  1322  (Mod32u <t> n (Const32 [c])) && isUnsignedPowerOfTwo(uint32(c)) => (And32 n (Const32 <t> [c-1]))
  1323  (Mod64u <t> n (Const64 [c])) && isUnsignedPowerOfTwo(uint64(c)) => (And64 n (Const64 <t> [c-1]))
  1324  
  1325  // Signed non-negative mod by power of 2 constant.
  1326  (Mod8  <t> n (Const8  [c])) && isNonNegative(n) && isPowerOfTwo(c) => (And8  n (Const8  <t> [c-1]))
  1327  (Mod16 <t> n (Const16 [c])) && isNonNegative(n) && isPowerOfTwo(c) => (And16 n (Const16 <t> [c-1]))
  1328  (Mod32 <t> n (Const32 [c])) && isNonNegative(n) && isPowerOfTwo(c) => (And32 n (Const32 <t> [c-1]))
  1329  (Mod64 <t> n (Const64 [c])) && isNonNegative(n) && isPowerOfTwo(c) => (And64 n (Const64 <t> [c-1]))
  1330  (Mod64 n (Const64 [-1<<63])) && isNonNegative(n)                   => n
  1331  
  1332  // Signed mod by negative constant.
  1333  (Mod8  <t> n (Const8  [c])) && c < 0 && c != -1<<7  => (Mod8  <t> n (Const8  <t> [-c]))
  1334  (Mod16 <t> n (Const16 [c])) && c < 0 && c != -1<<15 => (Mod16 <t> n (Const16 <t> [-c]))
  1335  (Mod32 <t> n (Const32 [c])) && c < 0 && c != -1<<31 => (Mod32 <t> n (Const32 <t> [-c]))
  1336  (Mod64 <t> n (Const64 [c])) && c < 0 && c != -1<<63 => (Mod64 <t> n (Const64 <t> [-c]))
  1337  
  1338  // All other mods by constants, do A%B = A-(A/B*B).
  1339  // This implements % with two * and a bunch of ancillary ops.
  1340  // One of the * is free if the user's code also computes A/B.
  1341  (Mod8   <t> x (Const8  [c])) && x.Op != OpConst8  && (c > 0 || c == -1<<7)
  1342    => (Sub8  x (Mul8  <t> (Div8   <t> x (Const8  <t> [c])) (Const8  <t> [c])))
  1343  (Mod16  <t> x (Const16 [c])) && x.Op != OpConst16 && (c > 0 || c == -1<<15)
  1344    => (Sub16 x (Mul16 <t> (Div16  <t> x (Const16 <t> [c])) (Const16 <t> [c])))
  1345  (Mod32  <t> x (Const32 [c])) && x.Op != OpConst32 && (c > 0 || c == -1<<31)
  1346    => (Sub32 x (Mul32 <t> (Div32  <t> x (Const32 <t> [c])) (Const32 <t> [c])))
  1347  (Mod64  <t> x (Const64 [c])) && x.Op != OpConst64 && (c > 0 || c == -1<<63)
  1348    => (Sub64 x (Mul64 <t> (Div64  <t> x (Const64 <t> [c])) (Const64 <t> [c])))
  1349  (Mod8u  <t> x (Const8  [c])) && x.Op != OpConst8  && c > 0 && umagicOK8( c)
  1350    => (Sub8  x (Mul8  <t> (Div8u  <t> x (Const8  <t> [c])) (Const8  <t> [c])))
  1351  (Mod16u <t> x (Const16 [c])) && x.Op != OpConst16 && c > 0 && umagicOK16(c)
  1352    => (Sub16 x (Mul16 <t> (Div16u <t> x (Const16 <t> [c])) (Const16 <t> [c])))
  1353  (Mod32u <t> x (Const32 [c])) && x.Op != OpConst32 && c > 0 && umagicOK32(c)
  1354    => (Sub32 x (Mul32 <t> (Div32u <t> x (Const32 <t> [c])) (Const32 <t> [c])))
  1355  (Mod64u <t> x (Const64 [c])) && x.Op != OpConst64 && c > 0 && umagicOK64(c)
  1356    => (Sub64 x (Mul64 <t> (Div64u <t> x (Const64 <t> [c])) (Const64 <t> [c])))
  1357  
  1358  // For architectures without rotates on less than 32-bits, promote these checks to 32-bit.
  1359  (Eq8 (Mod8u x (Const8  [c])) (Const8 [0])) && x.Op != OpConst8 && udivisibleOK8(c) && !hasSmallRotate(config) =>
  1360  	(Eq32 (Mod32u <typ.UInt32> (ZeroExt8to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(uint8(c))])) (Const32 <typ.UInt32> [0]))
  1361  (Eq16 (Mod16u x (Const16  [c])) (Const16 [0])) && x.Op != OpConst16 && udivisibleOK16(c) && !hasSmallRotate(config) =>
  1362  	(Eq32 (Mod32u <typ.UInt32> (ZeroExt16to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(uint16(c))])) (Const32 <typ.UInt32> [0]))
  1363  (Eq8 (Mod8 x (Const8  [c])) (Const8 [0])) && x.Op != OpConst8 && sdivisibleOK8(c) && !hasSmallRotate(config) =>
  1364  	(Eq32 (Mod32 <typ.Int32> (SignExt8to32 <typ.Int32> x) (Const32 <typ.Int32> [int32(c)])) (Const32 <typ.Int32> [0]))
  1365  (Eq16 (Mod16 x (Const16  [c])) (Const16 [0])) && x.Op != OpConst16 && sdivisibleOK16(c) && !hasSmallRotate(config) =>
  1366  	(Eq32 (Mod32 <typ.Int32> (SignExt16to32 <typ.Int32> x) (Const32 <typ.Int32> [int32(c)])) (Const32 <typ.Int32> [0]))
  1367  
  1368  // Divisibility checks x%c == 0 convert to multiply and rotate.
  1369  // Note, x%c == 0 is rewritten as x == c*(x/c) during the opt pass
  1370  // where (x/c) is performed using multiplication with magic constants.
  1371  // To rewrite x%c == 0 requires pattern matching the rewritten expression
  1372  // and checking that the division by the same constant wasn't already calculated.
  1373  // This check is made by counting uses of the magic constant multiplication.
  1374  // Note that if there were an intermediate opt pass, this rule could be applied
  1375  // directly on the Div op and magic division rewrites could be delayed to late opt.
  1376  
  1377  // Unsigned divisibility checks convert to multiply and rotate.
  1378  (Eq8 x (Mul8 (Const8 [c])
  1379    (Trunc32to8
  1380      (Rsh32Ux64
  1381        mul:(Mul32
  1382          (Const32 [m])
  1383          (ZeroExt8to32 x))
  1384        (Const64 [s])))
  1385  	)
  1386  )
  1387    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1388    && m == int32(1<<8+umagic8(c).m) && s == 8+umagic8(c).s
  1389    && x.Op != OpConst8 && udivisibleOK8(c)
  1390   => (Leq8U
  1391  			(RotateLeft8 <typ.UInt8>
  1392  				(Mul8 <typ.UInt8>
  1393  					(Const8 <typ.UInt8> [int8(udivisible8(c).m)])
  1394  					x)
  1395  				(Const8 <typ.UInt8> [int8(8-udivisible8(c).k)])
  1396  				)
  1397  			(Const8 <typ.UInt8> [int8(udivisible8(c).max)])
  1398  		)
  1399  
  1400  (Eq16 x (Mul16 (Const16 [c])
  1401    (Trunc64to16
  1402      (Rsh64Ux64
  1403        mul:(Mul64
  1404          (Const64 [m])
  1405          (ZeroExt16to64 x))
  1406        (Const64 [s])))
  1407  	)
  1408  )
  1409    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1410    && m == int64(1<<16+umagic16(c).m) && s == 16+umagic16(c).s
  1411    && x.Op != OpConst16 && udivisibleOK16(c)
  1412   => (Leq16U
  1413  			(RotateLeft16 <typ.UInt16>
  1414  				(Mul16 <typ.UInt16>
  1415  					(Const16 <typ.UInt16> [int16(udivisible16(c).m)])
  1416  					x)
  1417  				(Const16 <typ.UInt16> [int16(16-udivisible16(c).k)])
  1418  				)
  1419  			(Const16 <typ.UInt16> [int16(udivisible16(c).max)])
  1420  		)
  1421  
  1422  (Eq16 x (Mul16 (Const16 [c])
  1423    (Trunc32to16
  1424      (Rsh32Ux64
  1425        mul:(Mul32
  1426          (Const32 [m])
  1427          (ZeroExt16to32 x))
  1428        (Const64 [s])))
  1429  	)
  1430  )
  1431    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1432    && m == int32(1<<15+umagic16(c).m/2) && s == 16+umagic16(c).s-1
  1433    && x.Op != OpConst16 && udivisibleOK16(c)
  1434   => (Leq16U
  1435  			(RotateLeft16 <typ.UInt16>
  1436  				(Mul16 <typ.UInt16>
  1437  					(Const16 <typ.UInt16> [int16(udivisible16(c).m)])
  1438  					x)
  1439  				(Const16 <typ.UInt16> [int16(16-udivisible16(c).k)])
  1440  				)
  1441  			(Const16 <typ.UInt16> [int16(udivisible16(c).max)])
  1442  		)
  1443  
  1444  (Eq16 x (Mul16 (Const16 [c])
  1445    (Trunc32to16
  1446      (Rsh32Ux64
  1447        mul:(Mul32
  1448          (Const32 [m])
  1449          (Rsh32Ux64 (ZeroExt16to32 x) (Const64 [1])))
  1450        (Const64 [s])))
  1451  	)
  1452  )
  1453    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1454    && m == int32(1<<15+(umagic16(c).m+1)/2) && s == 16+umagic16(c).s-2
  1455    && x.Op != OpConst16 && udivisibleOK16(c)
  1456   => (Leq16U
  1457  			(RotateLeft16 <typ.UInt16>
  1458  				(Mul16 <typ.UInt16>
  1459  					(Const16 <typ.UInt16> [int16(udivisible16(c).m)])
  1460  					x)
  1461  				(Const16 <typ.UInt16> [int16(16-udivisible16(c).k)])
  1462  				)
  1463  			(Const16 <typ.UInt16> [int16(udivisible16(c).max)])
  1464  		)
  1465  
  1466  (Eq16 x (Mul16 (Const16 [c])
  1467    (Trunc32to16
  1468      (Rsh32Ux64
  1469        (Avg32u
  1470          (Lsh32x64 (ZeroExt16to32 x) (Const64 [16]))
  1471          mul:(Mul32
  1472            (Const32 [m])
  1473            (ZeroExt16to32 x)))
  1474        (Const64 [s])))
  1475  	)
  1476  )
  1477    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1478    && m == int32(umagic16(c).m) && s == 16+umagic16(c).s-1
  1479    && x.Op != OpConst16 && udivisibleOK16(c)
  1480   => (Leq16U
  1481  			(RotateLeft16 <typ.UInt16>
  1482  				(Mul16 <typ.UInt16>
  1483  					(Const16 <typ.UInt16> [int16(udivisible16(c).m)])
  1484  					x)
  1485  				(Const16 <typ.UInt16> [int16(16-udivisible16(c).k)])
  1486  				)
  1487  			(Const16 <typ.UInt16> [int16(udivisible16(c).max)])
  1488  		)
  1489  
  1490  (Eq32 x (Mul32 (Const32 [c])
  1491  	(Rsh32Ux64
  1492  		mul:(Hmul32u
  1493  			(Const32 [m])
  1494  			x)
  1495  		(Const64 [s]))
  1496  	)
  1497  )
  1498    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1499    && m == int32(1<<31+umagic32(c).m/2) && s == umagic32(c).s-1
  1500  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1501   => (Leq32U
  1502  			(RotateLeft32 <typ.UInt32>
  1503  				(Mul32 <typ.UInt32>
  1504  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1505  					x)
  1506  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1507  				)
  1508  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1509  		)
  1510  
  1511  (Eq32 x (Mul32 (Const32 [c])
  1512    (Rsh32Ux64
  1513      mul:(Hmul32u
  1514        (Const32 <typ.UInt32> [m])
  1515        (Rsh32Ux64 x (Const64 [1])))
  1516      (Const64 [s]))
  1517  	)
  1518  )
  1519    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1520    && m == int32(1<<31+(umagic32(c).m+1)/2) && s == umagic32(c).s-2
  1521  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1522   => (Leq32U
  1523  			(RotateLeft32 <typ.UInt32>
  1524  				(Mul32 <typ.UInt32>
  1525  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1526  					x)
  1527  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1528  				)
  1529  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1530  		)
  1531  
  1532  (Eq32 x (Mul32 (Const32 [c])
  1533    (Rsh32Ux64
  1534      (Avg32u
  1535        x
  1536        mul:(Hmul32u
  1537          (Const32 [m])
  1538          x))
  1539      (Const64 [s]))
  1540  	)
  1541  )
  1542    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1543    && m == int32(umagic32(c).m) && s == umagic32(c).s-1
  1544  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1545   => (Leq32U
  1546  			(RotateLeft32 <typ.UInt32>
  1547  				(Mul32 <typ.UInt32>
  1548  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1549  					x)
  1550  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1551  				)
  1552  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1553  		)
  1554  
  1555  (Eq32 x (Mul32 (Const32 [c])
  1556    (Trunc64to32
  1557      (Rsh64Ux64
  1558        mul:(Mul64
  1559          (Const64 [m])
  1560          (ZeroExt32to64 x))
  1561        (Const64 [s])))
  1562  	)
  1563  )
  1564    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1565    && m == int64(1<<31+umagic32(c).m/2) && s == 32+umagic32(c).s-1
  1566  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1567   => (Leq32U
  1568  			(RotateLeft32 <typ.UInt32>
  1569  				(Mul32 <typ.UInt32>
  1570  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1571  					x)
  1572  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1573  				)
  1574  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1575  		)
  1576  
  1577  (Eq32 x (Mul32 (Const32 [c])
  1578    (Trunc64to32
  1579      (Rsh64Ux64
  1580        mul:(Mul64
  1581          (Const64 [m])
  1582          (Rsh64Ux64 (ZeroExt32to64 x) (Const64 [1])))
  1583        (Const64 [s])))
  1584  	)
  1585  )
  1586    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1587    && m == int64(1<<31+(umagic32(c).m+1)/2) && s == 32+umagic32(c).s-2
  1588  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1589   => (Leq32U
  1590  			(RotateLeft32 <typ.UInt32>
  1591  				(Mul32 <typ.UInt32>
  1592  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1593  					x)
  1594  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1595  				)
  1596  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1597  		)
  1598  
  1599  (Eq32 x (Mul32 (Const32 [c])
  1600    (Trunc64to32
  1601      (Rsh64Ux64
  1602        (Avg64u
  1603          (Lsh64x64 (ZeroExt32to64 x) (Const64 [32]))
  1604          mul:(Mul64
  1605            (Const64 [m])
  1606            (ZeroExt32to64 x)))
  1607        (Const64 [s])))
  1608  	)
  1609  )
  1610    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1611    && m == int64(umagic32(c).m) && s == 32+umagic32(c).s-1
  1612  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1613   => (Leq32U
  1614  			(RotateLeft32 <typ.UInt32>
  1615  				(Mul32 <typ.UInt32>
  1616  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1617  					x)
  1618  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1619  				)
  1620  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1621  		)
  1622  
  1623  (Eq64 x (Mul64 (Const64 [c])
  1624  	(Rsh64Ux64
  1625  		mul:(Hmul64u
  1626  			(Const64 [m])
  1627  			x)
  1628  		(Const64 [s]))
  1629  	)
  1630  ) && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1631    && m == int64(1<<63+umagic64(c).m/2) && s == umagic64(c).s-1
  1632    && x.Op != OpConst64 && udivisibleOK64(c)
  1633   => (Leq64U
  1634  			(RotateLeft64 <typ.UInt64>
  1635  				(Mul64 <typ.UInt64>
  1636  					(Const64 <typ.UInt64> [int64(udivisible64(c).m)])
  1637  					x)
  1638  				(Const64 <typ.UInt64> [64-udivisible64(c).k])
  1639  				)
  1640  			(Const64 <typ.UInt64> [int64(udivisible64(c).max)])
  1641  		)
  1642  (Eq64 x (Mul64 (Const64 [c])
  1643  	(Rsh64Ux64
  1644  		mul:(Hmul64u
  1645  			(Const64 [m])
  1646  			(Rsh64Ux64 x (Const64 [1])))
  1647  		(Const64 [s]))
  1648  	)
  1649  ) && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1650    && m == int64(1<<63+(umagic64(c).m+1)/2) && s == umagic64(c).s-2
  1651    && x.Op != OpConst64 && udivisibleOK64(c)
  1652   => (Leq64U
  1653  			(RotateLeft64 <typ.UInt64>
  1654  				(Mul64 <typ.UInt64>
  1655  					(Const64 <typ.UInt64> [int64(udivisible64(c).m)])
  1656  					x)
  1657  				(Const64 <typ.UInt64> [64-udivisible64(c).k])
  1658  				)
  1659  			(Const64 <typ.UInt64> [int64(udivisible64(c).max)])
  1660  		)
  1661  (Eq64 x (Mul64 (Const64 [c])
  1662  	(Rsh64Ux64
  1663  		(Avg64u
  1664  			x
  1665  			mul:(Hmul64u
  1666  				(Const64 [m])
  1667  				x))
  1668  		(Const64 [s]))
  1669  	)
  1670  ) && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1671    && m == int64(umagic64(c).m) && s == umagic64(c).s-1
  1672    && x.Op != OpConst64 && udivisibleOK64(c)
  1673   => (Leq64U
  1674  			(RotateLeft64 <typ.UInt64>
  1675  				(Mul64 <typ.UInt64>
  1676  					(Const64 <typ.UInt64> [int64(udivisible64(c).m)])
  1677  					x)
  1678  				(Const64 <typ.UInt64> [64-udivisible64(c).k])
  1679  				)
  1680  			(Const64 <typ.UInt64> [int64(udivisible64(c).max)])
  1681  		)
  1682  
  1683  // Signed divisibility checks convert to multiply, add and rotate.
  1684  (Eq8 x (Mul8 (Const8 [c])
  1685    (Sub8
  1686      (Rsh32x64
  1687        mul:(Mul32
  1688          (Const32 [m])
  1689          (SignExt8to32 x))
  1690        (Const64 [s]))
  1691      (Rsh32x64
  1692        (SignExt8to32 x)
  1693        (Const64 [31])))
  1694  	)
  1695  )
  1696    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1697    && m == int32(smagic8(c).m) && s == 8+smagic8(c).s
  1698  	&& x.Op != OpConst8 && sdivisibleOK8(c)
  1699   => (Leq8U
  1700  			(RotateLeft8 <typ.UInt8>
  1701  				(Add8 <typ.UInt8>
  1702  					(Mul8 <typ.UInt8>
  1703  						(Const8 <typ.UInt8> [int8(sdivisible8(c).m)])
  1704  						x)
  1705  					(Const8 <typ.UInt8> [int8(sdivisible8(c).a)])
  1706  				)
  1707  				(Const8 <typ.UInt8> [int8(8-sdivisible8(c).k)])
  1708  			)
  1709  			(Const8 <typ.UInt8> [int8(sdivisible8(c).max)])
  1710  		)
  1711  
  1712  (Eq16 x (Mul16 (Const16 [c])
  1713    (Sub16
  1714      (Rsh32x64
  1715        mul:(Mul32
  1716          (Const32 [m])
  1717          (SignExt16to32 x))
  1718        (Const64 [s]))
  1719      (Rsh32x64
  1720        (SignExt16to32 x)
  1721        (Const64 [31])))
  1722  	)
  1723  )
  1724    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1725    && m == int32(smagic16(c).m) && s == 16+smagic16(c).s
  1726  	&& x.Op != OpConst16 && sdivisibleOK16(c)
  1727   => (Leq16U
  1728  			(RotateLeft16 <typ.UInt16>
  1729  				(Add16 <typ.UInt16>
  1730  					(Mul16 <typ.UInt16>
  1731  						(Const16 <typ.UInt16> [int16(sdivisible16(c).m)])
  1732  						x)
  1733  					(Const16 <typ.UInt16> [int16(sdivisible16(c).a)])
  1734  				)
  1735  				(Const16 <typ.UInt16> [int16(16-sdivisible16(c).k)])
  1736  			)
  1737  			(Const16 <typ.UInt16> [int16(sdivisible16(c).max)])
  1738  		)
  1739  
  1740  (Eq32 x (Mul32 (Const32 [c])
  1741    (Sub32
  1742      (Rsh64x64
  1743        mul:(Mul64
  1744          (Const64 [m])
  1745          (SignExt32to64 x))
  1746        (Const64 [s]))
  1747      (Rsh64x64
  1748        (SignExt32to64 x)
  1749        (Const64 [63])))
  1750  	)
  1751  )
  1752    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1753    && m == int64(smagic32(c).m) && s == 32+smagic32(c).s
  1754  	&& x.Op != OpConst32 && sdivisibleOK32(c)
  1755   => (Leq32U
  1756  			(RotateLeft32 <typ.UInt32>
  1757  				(Add32 <typ.UInt32>
  1758  					(Mul32 <typ.UInt32>
  1759  						(Const32 <typ.UInt32> [int32(sdivisible32(c).m)])
  1760  						x)
  1761  					(Const32 <typ.UInt32> [int32(sdivisible32(c).a)])
  1762  				)
  1763  				(Const32 <typ.UInt32> [int32(32-sdivisible32(c).k)])
  1764  			)
  1765  			(Const32 <typ.UInt32> [int32(sdivisible32(c).max)])
  1766  		)
  1767  
  1768  (Eq32 x (Mul32 (Const32 [c])
  1769    (Sub32
  1770      (Rsh32x64
  1771        mul:(Hmul32
  1772          (Const32 [m])
  1773          x)
  1774        (Const64 [s]))
  1775      (Rsh32x64
  1776        x
  1777        (Const64 [31])))
  1778  	)
  1779  )
  1780    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1781    && m == int32(smagic32(c).m/2) && s == smagic32(c).s-1
  1782  	&& x.Op != OpConst32 && sdivisibleOK32(c)
  1783   => (Leq32U
  1784  			(RotateLeft32 <typ.UInt32>
  1785  				(Add32 <typ.UInt32>
  1786  					(Mul32 <typ.UInt32>
  1787  						(Const32 <typ.UInt32> [int32(sdivisible32(c).m)])
  1788  						x)
  1789  					(Const32 <typ.UInt32> [int32(sdivisible32(c).a)])
  1790  				)
  1791  				(Const32 <typ.UInt32> [int32(32-sdivisible32(c).k)])
  1792  			)
  1793  			(Const32 <typ.UInt32> [int32(sdivisible32(c).max)])
  1794  		)
  1795  
  1796  (Eq32 x (Mul32 (Const32 [c])
  1797    (Sub32
  1798      (Rsh32x64
  1799        (Add32
  1800          mul:(Hmul32
  1801            (Const32 [m])
  1802            x)
  1803          x)
  1804        (Const64 [s]))
  1805      (Rsh32x64
  1806        x
  1807        (Const64 [31])))
  1808  	)
  1809  )
  1810    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1811    && m == int32(smagic32(c).m) && s == smagic32(c).s
  1812  	&& x.Op != OpConst32 && sdivisibleOK32(c)
  1813   => (Leq32U
  1814  			(RotateLeft32 <typ.UInt32>
  1815  				(Add32 <typ.UInt32>
  1816  					(Mul32 <typ.UInt32>
  1817  						(Const32 <typ.UInt32> [int32(sdivisible32(c).m)])
  1818  						x)
  1819  					(Const32 <typ.UInt32> [int32(sdivisible32(c).a)])
  1820  				)
  1821  				(Const32 <typ.UInt32> [int32(32-sdivisible32(c).k)])
  1822  			)
  1823  			(Const32 <typ.UInt32> [int32(sdivisible32(c).max)])
  1824  		)
  1825  
  1826  (Eq64 x (Mul64 (Const64 [c])
  1827    (Sub64
  1828      (Rsh64x64
  1829        mul:(Hmul64
  1830          (Const64 [m])
  1831          x)
  1832        (Const64 [s]))
  1833      (Rsh64x64
  1834        x
  1835        (Const64 [63])))
  1836  	)
  1837  )
  1838    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1839    && m == int64(smagic64(c).m/2) && s == smagic64(c).s-1
  1840  	&& x.Op != OpConst64 && sdivisibleOK64(c)
  1841   => (Leq64U
  1842  			(RotateLeft64 <typ.UInt64>
  1843  				(Add64 <typ.UInt64>
  1844  					(Mul64 <typ.UInt64>
  1845  						(Const64 <typ.UInt64> [int64(sdivisible64(c).m)])
  1846  						x)
  1847  					(Const64 <typ.UInt64> [int64(sdivisible64(c).a)])
  1848  				)
  1849  				(Const64 <typ.UInt64> [64-sdivisible64(c).k])
  1850  			)
  1851  			(Const64 <typ.UInt64> [int64(sdivisible64(c).max)])
  1852  		)
  1853  
  1854  (Eq64 x (Mul64 (Const64 [c])
  1855    (Sub64
  1856      (Rsh64x64
  1857        (Add64
  1858          mul:(Hmul64
  1859            (Const64 [m])
  1860            x)
  1861          x)
  1862        (Const64 [s]))
  1863      (Rsh64x64
  1864        x
  1865        (Const64 [63])))
  1866  	)
  1867  )
  1868    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1869    && m == int64(smagic64(c).m) && s == smagic64(c).s
  1870  	&& x.Op != OpConst64 && sdivisibleOK64(c)
  1871   => (Leq64U
  1872  			(RotateLeft64 <typ.UInt64>
  1873  				(Add64 <typ.UInt64>
  1874  					(Mul64 <typ.UInt64>
  1875  						(Const64 <typ.UInt64> [int64(sdivisible64(c).m)])
  1876  						x)
  1877  					(Const64 <typ.UInt64> [int64(sdivisible64(c).a)])
  1878  				)
  1879  				(Const64 <typ.UInt64> [64-sdivisible64(c).k])
  1880  			)
  1881  			(Const64 <typ.UInt64> [int64(sdivisible64(c).max)])
  1882  		)
  1883  
  1884  // Divisibility check for signed integers for power of two constant are simple mask.
  1885  // However, we must match against the rewritten n%c == 0 -> n - c*(n/c) == 0 -> n == c*(n/c)
  1886  // where n/c contains fixup code to handle signed n.
  1887  ((Eq8|Neq8) n (Lsh8x64
  1888    (Rsh8x64
  1889      (Add8  <t> n (Rsh8Ux64  <t> (Rsh8x64  <t> n (Const64 <typ.UInt64> [ 7])) (Const64 <typ.UInt64> [kbar])))
  1890      (Const64 <typ.UInt64> [k]))
  1891  	(Const64 <typ.UInt64> [k]))
  1892  ) && k > 0 && k < 7 && kbar == 8 - k
  1893    => ((Eq8|Neq8) (And8 <t> n (Const8 <t> [1<<uint(k)-1])) (Const8 <t> [0]))
  1894  
  1895  ((Eq16|Neq16) n (Lsh16x64
  1896    (Rsh16x64
  1897      (Add16 <t> n (Rsh16Ux64 <t> (Rsh16x64 <t> n (Const64 <typ.UInt64> [15])) (Const64 <typ.UInt64> [kbar])))
  1898      (Const64 <typ.UInt64> [k]))
  1899  	(Const64 <typ.UInt64> [k]))
  1900  ) && k > 0 && k < 15 && kbar == 16 - k
  1901    => ((Eq16|Neq16) (And16 <t> n (Const16 <t> [1<<uint(k)-1])) (Const16 <t> [0]))
  1902  
  1903  ((Eq32|Neq32) n (Lsh32x64
  1904    (Rsh32x64
  1905      (Add32 <t> n (Rsh32Ux64 <t> (Rsh32x64 <t> n (Const64 <typ.UInt64> [31])) (Const64 <typ.UInt64> [kbar])))
  1906      (Const64 <typ.UInt64> [k]))
  1907  	(Const64 <typ.UInt64> [k]))
  1908  ) && k > 0 && k < 31 && kbar == 32 - k
  1909    => ((Eq32|Neq32) (And32 <t> n (Const32 <t> [1<<uint(k)-1])) (Const32 <t> [0]))
  1910  
  1911  ((Eq64|Neq64) n (Lsh64x64
  1912    (Rsh64x64
  1913      (Add64 <t> n (Rsh64Ux64 <t> (Rsh64x64 <t> n (Const64 <typ.UInt64> [63])) (Const64 <typ.UInt64> [kbar])))
  1914      (Const64 <typ.UInt64> [k]))
  1915  	(Const64 <typ.UInt64> [k]))
  1916  ) && k > 0 && k < 63 && kbar == 64 - k
  1917    => ((Eq64|Neq64) (And64 <t> n (Const64 <t> [1<<uint(k)-1])) (Const64 <t> [0]))
  1918  
  1919  (Eq(8|16|32|64)  s:(Sub(8|16|32|64) x y) (Const(8|16|32|64) [0])) && s.Uses == 1 => (Eq(8|16|32|64)  x y)
  1920  (Neq(8|16|32|64) s:(Sub(8|16|32|64) x y) (Const(8|16|32|64) [0])) && s.Uses == 1 => (Neq(8|16|32|64) x y)
  1921  
  1922  // Optimize bitsets
  1923  (Eq(8|16|32|64) (And(8|16|32|64) <t> x (Const(8|16|32|64) <t> [y])) (Const(8|16|32|64) <t> [y])) && oneBit(y)
  1924    => (Neq(8|16|32|64) (And(8|16|32|64) <t> x (Const(8|16|32|64) <t> [y])) (Const(8|16|32|64) <t> [0]))
  1925  (Neq(8|16|32|64) (And(8|16|32|64) <t> x (Const(8|16|32|64) <t> [y])) (Const(8|16|32|64) <t> [y])) && oneBit(y)
  1926    => (Eq(8|16|32|64) (And(8|16|32|64) <t> x (Const(8|16|32|64) <t> [y])) (Const(8|16|32|64) <t> [0]))
  1927  
  1928  // Reassociate expressions involving
  1929  // constants such that constants come first,
  1930  // exposing obvious constant-folding opportunities.
  1931  // Reassociate (op (op y C) x) to (op C (op x y)) or similar, where C
  1932  // is constant, which pushes constants to the outside
  1933  // of the expression. At that point, any constant-folding
  1934  // opportunities should be obvious.
  1935  // Note: don't include AddPtr here! In order to maintain the
  1936  // invariant that pointers must stay within the pointed-to object,
  1937  // we can't pull part of a pointer computation above the AddPtr.
  1938  // See issue 37881.
  1939  // Note: we don't need to handle any (x-C) cases because we already rewrite
  1940  // (x-C) to (x+(-C)).
  1941  
  1942  // x + (C + z) -> C + (x + z)
  1943  (Add64 (Add64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Add64 i (Add64 <t> z x))
  1944  (Add32 (Add32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Add32 i (Add32 <t> z x))
  1945  (Add16 (Add16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Add16 i (Add16 <t> z x))
  1946  (Add8  (Add8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Add8  i (Add8  <t> z x))
  1947  
  1948  // x + (C - z) -> C + (x - z)
  1949  (Add64 (Sub64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Add64 i (Sub64 <t> x z))
  1950  (Add32 (Sub32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Add32 i (Sub32 <t> x z))
  1951  (Add16 (Sub16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Add16 i (Sub16 <t> x z))
  1952  (Add8  (Sub8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Add8  i (Sub8  <t> x z))
  1953  
  1954  // x - (C - z) -> x + (z - C) -> (x + z) - C
  1955  (Sub64 x (Sub64 i:(Const64 <t>) z)) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 (Add64 <t> x z) i)
  1956  (Sub32 x (Sub32 i:(Const32 <t>) z)) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 (Add32 <t> x z) i)
  1957  (Sub16 x (Sub16 i:(Const16 <t>) z)) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 (Add16 <t> x z) i)
  1958  (Sub8  x (Sub8  i:(Const8  <t>) z)) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8  (Add8  <t> x z) i)
  1959  
  1960  // x - (z + C) -> x + (-z - C) -> (x - z) - C
  1961  (Sub64 x (Add64 z i:(Const64 <t>))) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 (Sub64 <t> x z) i)
  1962  (Sub32 x (Add32 z i:(Const32 <t>))) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 (Sub32 <t> x z) i)
  1963  (Sub16 x (Add16 z i:(Const16 <t>))) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 (Sub16 <t> x z) i)
  1964  (Sub8  x (Add8  z i:(Const8  <t>))) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8 (Sub8  <t> x z) i)
  1965  
  1966  // (C - z) - x -> C - (z + x)
  1967  (Sub64 (Sub64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 i (Add64 <t> z x))
  1968  (Sub32 (Sub32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 i (Add32 <t> z x))
  1969  (Sub16 (Sub16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 i (Add16 <t> z x))
  1970  (Sub8  (Sub8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8  i (Add8  <t> z x))
  1971  
  1972  // (z + C) -x -> C + (z - x)
  1973  (Sub64 (Add64 z i:(Const64 <t>)) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Add64 i (Sub64 <t> z x))
  1974  (Sub32 (Add32 z i:(Const32 <t>)) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Add32 i (Sub32 <t> z x))
  1975  (Sub16 (Add16 z i:(Const16 <t>)) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Add16 i (Sub16 <t> z x))
  1976  (Sub8  (Add8  z i:(Const8  <t>)) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Add8  i (Sub8  <t> z x))
  1977  
  1978  // x & (C & z) -> C & (x & z)
  1979  (And64 (And64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (And64 i (And64 <t> z x))
  1980  (And32 (And32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (And32 i (And32 <t> z x))
  1981  (And16 (And16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (And16 i (And16 <t> z x))
  1982  (And8  (And8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (And8  i (And8  <t> z x))
  1983  
  1984  // x | (C | z) -> C | (x | z)
  1985  (Or64 (Or64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Or64 i (Or64 <t> z x))
  1986  (Or32 (Or32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Or32 i (Or32 <t> z x))
  1987  (Or16 (Or16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Or16 i (Or16 <t> z x))
  1988  (Or8  (Or8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Or8  i (Or8  <t> z x))
  1989  
  1990  // x ^ (C ^ z) -> C ^ (x ^ z)
  1991  (Xor64 (Xor64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Xor64 i (Xor64 <t> z x))
  1992  (Xor32 (Xor32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Xor32 i (Xor32 <t> z x))
  1993  (Xor16 (Xor16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Xor16 i (Xor16 <t> z x))
  1994  (Xor8  (Xor8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Xor8  i (Xor8  <t> z x))
  1995  
  1996  // x * (D * z) = D * (x * z)
  1997  (Mul64 (Mul64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Mul64 i (Mul64 <t> x z))
  1998  (Mul32 (Mul32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Mul32 i (Mul32 <t> x z))
  1999  (Mul16 (Mul16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Mul16 i (Mul16 <t> x z))
  2000  (Mul8  (Mul8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Mul8  i (Mul8  <t> x z))
  2001  
  2002  // C + (D + x) -> (C + D) + x
  2003  (Add64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Add64 (Const64 <t> [c+d]) x)
  2004  (Add32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Add32 (Const32 <t> [c+d]) x)
  2005  (Add16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Add16 (Const16 <t> [c+d]) x)
  2006  (Add8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Add8  (Const8  <t> [c+d]) x)
  2007  
  2008  // C + (D - x) -> (C + D) - x
  2009  (Add64 (Const64 <t> [c]) (Sub64 (Const64 <t> [d]) x)) => (Sub64 (Const64 <t> [c+d]) x)
  2010  (Add32 (Const32 <t> [c]) (Sub32 (Const32 <t> [d]) x)) => (Sub32 (Const32 <t> [c+d]) x)
  2011  (Add16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) => (Sub16 (Const16 <t> [c+d]) x)
  2012  (Add8  (Const8  <t> [c]) (Sub8  (Const8  <t> [d]) x)) => (Sub8  (Const8  <t> [c+d]) x)
  2013  
  2014  // C - (D - x) -> (C - D) + x
  2015  (Sub64 (Const64 <t> [c]) (Sub64 (Const64 <t> [d]) x)) => (Add64 (Const64 <t> [c-d]) x)
  2016  (Sub32 (Const32 <t> [c]) (Sub32 (Const32 <t> [d]) x)) => (Add32 (Const32 <t> [c-d]) x)
  2017  (Sub16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) => (Add16 (Const16 <t> [c-d]) x)
  2018  (Sub8  (Const8  <t> [c]) (Sub8  (Const8  <t> [d]) x)) => (Add8  (Const8  <t> [c-d]) x)
  2019  
  2020  // C - (D + x) -> (C - D) - x
  2021  (Sub64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Sub64 (Const64 <t> [c-d]) x)
  2022  (Sub32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Sub32 (Const32 <t> [c-d]) x)
  2023  (Sub16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Sub16 (Const16 <t> [c-d]) x)
  2024  (Sub8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Sub8  (Const8  <t> [c-d]) x)
  2025  
  2026  // C & (D & x) -> (C & D) & x
  2027  (And64 (Const64 <t> [c]) (And64 (Const64 <t> [d]) x)) => (And64 (Const64 <t> [c&d]) x)
  2028  (And32 (Const32 <t> [c]) (And32 (Const32 <t> [d]) x)) => (And32 (Const32 <t> [c&d]) x)
  2029  (And16 (Const16 <t> [c]) (And16 (Const16 <t> [d]) x)) => (And16 (Const16 <t> [c&d]) x)
  2030  (And8  (Const8  <t> [c]) (And8  (Const8  <t> [d]) x)) => (And8  (Const8  <t> [c&d]) x)
  2031  
  2032  // C | (D | x) -> (C | D) | x
  2033  (Or64 (Const64 <t> [c]) (Or64 (Const64 <t> [d]) x)) => (Or64 (Const64 <t> [c|d]) x)
  2034  (Or32 (Const32 <t> [c]) (Or32 (Const32 <t> [d]) x)) => (Or32 (Const32 <t> [c|d]) x)
  2035  (Or16 (Const16 <t> [c]) (Or16 (Const16 <t> [d]) x)) => (Or16 (Const16 <t> [c|d]) x)
  2036  (Or8  (Const8  <t> [c]) (Or8  (Const8  <t> [d]) x)) => (Or8  (Const8  <t> [c|d]) x)
  2037  
  2038  // C ^ (D ^ x) -> (C ^ D) ^ x
  2039  (Xor64 (Const64 <t> [c]) (Xor64 (Const64 <t> [d]) x)) => (Xor64 (Const64 <t> [c^d]) x)
  2040  (Xor32 (Const32 <t> [c]) (Xor32 (Const32 <t> [d]) x)) => (Xor32 (Const32 <t> [c^d]) x)
  2041  (Xor16 (Const16 <t> [c]) (Xor16 (Const16 <t> [d]) x)) => (Xor16 (Const16 <t> [c^d]) x)
  2042  (Xor8  (Const8  <t> [c]) (Xor8  (Const8  <t> [d]) x)) => (Xor8  (Const8  <t> [c^d]) x)
  2043  
  2044  // C * (D * x) = (C * D) * x
  2045  (Mul64 (Const64 <t> [c]) (Mul64 (Const64 <t> [d]) x)) => (Mul64 (Const64 <t> [c*d]) x)
  2046  (Mul32 (Const32 <t> [c]) (Mul32 (Const32 <t> [d]) x)) => (Mul32 (Const32 <t> [c*d]) x)
  2047  (Mul16 (Const16 <t> [c]) (Mul16 (Const16 <t> [d]) x)) => (Mul16 (Const16 <t> [c*d]) x)
  2048  (Mul8  (Const8  <t> [c]) (Mul8  (Const8  <t> [d]) x)) => (Mul8  (Const8  <t> [c*d]) x)
  2049  
  2050  // floating point optimizations
  2051  (Mul(32|64)F x (Const(32|64)F [1])) => x
  2052  (Mul32F x (Const32F [-1])) => (Neg32F x)
  2053  (Mul64F x (Const64F [-1])) => (Neg64F x)
  2054  (Mul32F x (Const32F [2])) => (Add32F x x)
  2055  (Mul64F x (Const64F [2])) => (Add64F x x)
  2056  
  2057  (Div32F x (Const32F <t> [c])) && reciprocalExact32(c) => (Mul32F x (Const32F <t> [1/c]))
  2058  (Div64F x (Const64F <t> [c])) && reciprocalExact64(c) => (Mul64F x (Const64F <t> [1/c]))
  2059  
  2060  // rewrite single-precision sqrt expression "float32(math.Sqrt(float64(x)))"
  2061  (Cvt64Fto32F sqrt0:(Sqrt (Cvt32Fto64F x))) && sqrt0.Uses==1 => (Sqrt32 x)
  2062  
  2063  (Sqrt (Const64F [c])) && !math.IsNaN(math.Sqrt(c)) => (Const64F [math.Sqrt(c)])
  2064  
  2065  // for rewriting constant folded math/bits ops
  2066  (Select0 (MakeTuple x y)) => x
  2067  (Select1 (MakeTuple x y)) => y
  2068  
  2069  // for rewriting results of some late-expanded rewrites (below)
  2070  (SelectN [n] m:(MakeResult ___)) => m.Args[n]
  2071  
  2072  // TODO(matloob): Try out having non-zeroing mallocs for prointerless
  2073  // memory, and leaving the zeroing here. Then the compiler can remove
  2074  // the zeroing if the user has explicit writes to the whole object.
  2075  
  2076  // for late-expanded calls, recognize newobject and remove zeroing and nilchecks
  2077  (Zero (SelectN [0] call:(StaticLECall ___)) mem:(SelectN [1] call))
  2078  	&& isMalloc(call.Aux)
  2079  	=> mem
  2080  
  2081  (Store (SelectN [0] call:(StaticLECall ___)) x mem:(SelectN [1] call))
  2082  	&& isConstZero(x)
  2083  	&& isMalloc(call.Aux)
  2084  	=> mem
  2085  
  2086  (Store (OffPtr (SelectN [0] call:(StaticLECall ___))) x mem:(SelectN [1] call))
  2087  	&& isConstZero(x)
  2088  	&& isMalloc(call.Aux)
  2089  	=> mem
  2090  
  2091  (NilCheck ptr:(SelectN [0] call:(StaticLECall ___)) _)
  2092  	&& isMalloc(call.Aux)
  2093  	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
  2094  	=> ptr
  2095  
  2096  (NilCheck ptr:(OffPtr (SelectN [0] call:(StaticLECall ___))) _)
  2097  	&& isMalloc(call.Aux)
  2098  	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
  2099  	=> ptr
  2100  
  2101  // Addresses of globals are always non-nil.
  2102  (NilCheck          ptr:(Addr {_} (SB))    _) => ptr
  2103  (NilCheck ptr:(Convert (Addr {_} (SB)) _) _) => ptr
  2104  
  2105  // Addresses of locals are always non-nil.
  2106  (NilCheck ptr:(LocalAddr _ _) _)
  2107  	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
  2108  	=> ptr
  2109  
  2110  // .dict args are always non-nil.
  2111  (NilCheck ptr:(Arg {sym}) _) && isDictArgSym(sym) => ptr
  2112  
  2113  // Nil checks of nil checks are redundant.
  2114  // See comment at the end of https://go-review.googlesource.com/c/go/+/537775.
  2115  (NilCheck ptr:(NilCheck _ _) _ ) => ptr
  2116  
  2117  // for late-expanded calls, recognize memequal applied to a single constant byte
  2118  // Support is limited by [1-8] byte sizes
  2119  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [1]) mem)
  2120    && isSameCall(callAux, "runtime.memequal")
  2121    && symIsRO(scon)
  2122    => (MakeResult (Eq8 (Load <typ.Int8> sptr mem) (Const8 <typ.Int8> [int8(read8(scon,0))])) mem)
  2123  
  2124  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [1]) mem)
  2125    && isSameCall(callAux, "runtime.memequal")
  2126    && symIsRO(scon)
  2127    => (MakeResult (Eq8 (Load <typ.Int8> sptr mem) (Const8 <typ.Int8> [int8(read8(scon,0))])) mem)
  2128  
  2129  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [2]) mem)
  2130    && isSameCall(callAux, "runtime.memequal")
  2131    && symIsRO(scon)
  2132    && canLoadUnaligned(config)
  2133    => (MakeResult (Eq16 (Load <typ.Int16> sptr mem) (Const16 <typ.Int16> [int16(read16(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2134  
  2135  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [2]) mem)
  2136    && isSameCall(callAux, "runtime.memequal")
  2137    && symIsRO(scon)
  2138    && canLoadUnaligned(config)
  2139    => (MakeResult (Eq16 (Load <typ.Int16> sptr mem) (Const16 <typ.Int16> [int16(read16(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2140  
  2141  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [4]) mem)
  2142    && isSameCall(callAux, "runtime.memequal")
  2143    && symIsRO(scon)
  2144    && canLoadUnaligned(config)
  2145    => (MakeResult (Eq32 (Load <typ.Int32> sptr mem) (Const32 <typ.Int32> [int32(read32(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2146  
  2147  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [4]) mem)
  2148    && isSameCall(callAux, "runtime.memequal")
  2149    && symIsRO(scon)
  2150    && canLoadUnaligned(config)
  2151    => (MakeResult (Eq32 (Load <typ.Int32> sptr mem) (Const32 <typ.Int32> [int32(read32(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2152  
  2153  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [8]) mem)
  2154    && isSameCall(callAux, "runtime.memequal")
  2155    && symIsRO(scon)
  2156    && canLoadUnaligned(config) && config.PtrSize == 8
  2157    => (MakeResult (Eq64 (Load <typ.Int64> sptr mem) (Const64 <typ.Int64> [int64(read64(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2158  
  2159  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [8]) mem)
  2160    && isSameCall(callAux, "runtime.memequal")
  2161    && symIsRO(scon)
  2162    && canLoadUnaligned(config) && config.PtrSize == 8
  2163    => (MakeResult (Eq64 (Load <typ.Int64> sptr mem) (Const64 <typ.Int64> [int64(read64(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2164  
  2165  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [3]) mem)
  2166    && isSameCall(callAux, "runtime.memequal")
  2167    && symIsRO(scon)
  2168    && canLoadUnaligned(config) =>
  2169    (MakeResult
  2170      (Eq32
  2171        (Or32 <typ.Int32>
  2172          (ZeroExt16to32 <typ.Int32> (Load <typ.Int16> sptr mem))
  2173          (Lsh32x32 <typ.Int32>
  2174            (ZeroExt8to32 <typ.Int32> (Load <typ.Int8> (OffPtr <typ.BytePtr> [2] sptr) mem))
  2175            (Const32 <typ.Int32> [16])))
  2176        (Const32 <typ.Int32> [int32(uint32(read16(scon,0,config.ctxt.Arch.ByteOrder))|(uint32(read8(scon,2))<<16))]))
  2177      mem)
  2178  
  2179  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [3]) mem)
  2180    && isSameCall(callAux, "runtime.memequal")
  2181    && symIsRO(scon)
  2182    && canLoadUnaligned(config) =>
  2183    (MakeResult
  2184      (Eq32
  2185        (Or32 <typ.Int32>
  2186          (ZeroExt16to32 <typ.Int32> (Load <typ.Int16> sptr mem))
  2187          (Lsh32x32 <typ.Int32>
  2188            (ZeroExt8to32 <typ.Int32> (Load <typ.Int8> (OffPtr <typ.BytePtr> [2] sptr) mem))
  2189            (Const32 <typ.Int32> [16])))
  2190        (Const32 <typ.Int32> [int32(uint32(read16(scon,0,config.ctxt.Arch.ByteOrder))|(uint32(read8(scon,2))<<16))]))
  2191      mem)
  2192  
  2193  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [5]) mem)
  2194    && isSameCall(callAux, "runtime.memequal")
  2195    && symIsRO(scon)
  2196    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  2197    (MakeResult
  2198      (Eq64
  2199        (Or64 <typ.Int64>
  2200          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  2201          (Lsh64x64 <typ.Int64>
  2202            (ZeroExt8to64 <typ.Int64> (Load <typ.Int8> (OffPtr <typ.BytePtr> [4] sptr) mem))
  2203            (Const64 <typ.Int64> [32])))
  2204        (Const64 <typ.Int64> [int64(uint64(read32(scon,0,config.ctxt.Arch.ByteOrder))|(uint64(read8(scon,4))<<32))]))
  2205      mem)
  2206  
  2207  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [5]) mem)
  2208    && isSameCall(callAux, "runtime.memequal")
  2209    && symIsRO(scon)
  2210    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  2211    (MakeResult
  2212      (Eq64
  2213        (Or64 <typ.Int64>
  2214          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  2215          (Lsh64x64 <typ.Int64>
  2216            (ZeroExt8to64 <typ.Int64> (Load <typ.Int8> (OffPtr <typ.BytePtr> [4] sptr) mem))
  2217            (Const64 <typ.Int64> [32])))
  2218        (Const64 <typ.Int64> [int64(uint64(read32(scon,0,config.ctxt.Arch.ByteOrder))|(uint64(read8(scon,4))<<32))]))
  2219      mem)
  2220  
  2221  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [6]) mem)
  2222    && isSameCall(callAux, "runtime.memequal")
  2223    && symIsRO(scon)
  2224    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  2225    (MakeResult
  2226      (Eq64
  2227        (Or64 <typ.Int64>
  2228          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  2229          (Lsh64x64 <typ.Int64>
  2230            (ZeroExt16to64 <typ.Int64> (Load <typ.Int16> (OffPtr <typ.BytePtr> [4] sptr) mem))
  2231            (Const64 <typ.Int64> [32])))
  2232        (Const64 <typ.Int64> [int64(uint64(read32(scon,0,config.ctxt.Arch.ByteOrder))|(uint64(read16(scon,4,config.ctxt.Arch.ByteOrder))<<32))]))
  2233      mem)
  2234  
  2235  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [6]) mem)
  2236    && isSameCall(callAux, "runtime.memequal")
  2237    && symIsRO(scon)
  2238    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  2239    (MakeResult
  2240      (Eq64
  2241        (Or64 <typ.Int64>
  2242          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  2243          (Lsh64x64 <typ.Int64>
  2244            (ZeroExt16to64 <typ.Int64> (Load <typ.Int16> (OffPtr <typ.BytePtr> [4] sptr) mem))
  2245            (Const64 <typ.Int64> [32])))
  2246        (Const64 <typ.Int64> [int64(uint64(read32(scon,0,config.ctxt.Arch.ByteOrder))|(uint64(read16(scon,4,config.ctxt.Arch.ByteOrder))<<32))]))
  2247      mem)
  2248  
  2249  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [7]) mem)
  2250    && isSameCall(callAux, "runtime.memequal")
  2251    && symIsRO(scon)
  2252    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  2253    (MakeResult
  2254      (Eq64
  2255        (Or64 <typ.Int64>
  2256          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  2257          (Lsh64x64 <typ.Int64>
  2258            (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> (OffPtr <typ.BytePtr> [3] sptr) mem))
  2259            (Const64 <typ.Int64> [32])))
  2260        (Const64 <typ.Int64> [int64(uint64(read32(scon,0,config.ctxt.Arch.ByteOrder))|(uint64(read32(scon,3,config.ctxt.Arch.ByteOrder))<<32))]))
  2261      mem)
  2262  
  2263  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [7]) mem)
  2264    && isSameCall(callAux, "runtime.memequal")
  2265    && symIsRO(scon)
  2266    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  2267    (MakeResult
  2268      (Eq64
  2269        (Or64 <typ.Int64>
  2270          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  2271          (Lsh64x64 <typ.Int64>
  2272            (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> (OffPtr <typ.BytePtr> [3] sptr) mem))
  2273            (Const64 <typ.Int64> [32])))
  2274        (Const64 <typ.Int64> [int64(uint64(read32(scon,0,config.ctxt.Arch.ByteOrder))|(uint64(read32(scon,3,config.ctxt.Arch.ByteOrder))<<32))]))
  2275      mem)
  2276  
  2277  (StaticLECall {callAux} _ _ (Const64 [0]) mem)
  2278    && isSameCall(callAux, "runtime.memequal")
  2279    => (MakeResult (ConstBool <typ.Bool> [true]) mem)
  2280  
  2281  (Static(Call|LECall) {callAux} p q _ mem)
  2282    && isSameCall(callAux, "runtime.memequal")
  2283    && isSamePtr(p, q)
  2284    => (MakeResult (ConstBool <typ.Bool> [true]) mem)
  2285  
  2286  // Turn known-size calls to memclrNoHeapPointers into a Zero.
  2287  // Note that we are using types.Types[types.TUINT8] instead of sptr.Type.Elem() - see issue 55122 and CL 431496 for more details.
  2288  (SelectN [0] call:(StaticCall {sym} sptr (Const(64|32) [c]) mem))
  2289    && isInlinableMemclr(config, int64(c))
  2290    && isSameCall(sym, "runtime.memclrNoHeapPointers")
  2291    && call.Uses == 1
  2292    && clobber(call)
  2293    => (Zero {types.Types[types.TUINT8]} [int64(c)] sptr mem)
  2294  
  2295  // Recognise make([]T, 0) and replace it with a pointer to the zerobase
  2296  (StaticLECall {callAux} _ (Const(64|32) [0]) (Const(64|32) [0]) mem)
  2297  	&& isSameCall(callAux, "runtime.makeslice")
  2298  	=> (MakeResult (Addr <v.Type.FieldType(0)> {ir.Syms.Zerobase} (SB)) mem)
  2299  
  2300  // Evaluate constant address comparisons.
  2301  (EqPtr  x x) => (ConstBool [true])
  2302  (NeqPtr x x) => (ConstBool [false])
  2303  (EqPtr  (Addr {x} _) (Addr {y} _)) => (ConstBool [x == y])
  2304  (EqPtr  (Addr {x} _) (OffPtr [o] (Addr {y} _))) => (ConstBool [x == y && o == 0])
  2305  (EqPtr  (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _))) => (ConstBool [x == y && o1 == o2])
  2306  (NeqPtr (Addr {x} _) (Addr {y} _)) => (ConstBool [x != y])
  2307  (NeqPtr (Addr {x} _) (OffPtr [o] (Addr {y} _))) => (ConstBool [x != y || o != 0])
  2308  (NeqPtr (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _))) => (ConstBool [x != y || o1 != o2])
  2309  (EqPtr  (LocalAddr {x} _ _) (LocalAddr {y} _ _)) => (ConstBool [x == y])
  2310  (EqPtr  (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _))) => (ConstBool [x == y && o == 0])
  2311  (EqPtr  (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _))) => (ConstBool [x == y && o1 == o2])
  2312  (NeqPtr (LocalAddr {x} _ _) (LocalAddr {y} _ _)) => (ConstBool [x != y])
  2313  (NeqPtr (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _))) => (ConstBool [x != y || o != 0])
  2314  (NeqPtr (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _))) => (ConstBool [x != y || o1 != o2])
  2315  (EqPtr  (OffPtr [o1] p1) p2) && isSamePtr(p1, p2) => (ConstBool [o1 == 0])
  2316  (NeqPtr (OffPtr [o1] p1) p2) && isSamePtr(p1, p2) => (ConstBool [o1 != 0])
  2317  (EqPtr  (OffPtr [o1] p1) (OffPtr [o2] p2)) && isSamePtr(p1, p2) => (ConstBool [o1 == o2])
  2318  (NeqPtr (OffPtr [o1] p1) (OffPtr [o2] p2)) && isSamePtr(p1, p2) => (ConstBool [o1 != o2])
  2319  (EqPtr  (Const(32|64) [c]) (Const(32|64) [d])) => (ConstBool [c == d])
  2320  (NeqPtr (Const(32|64) [c]) (Const(32|64) [d])) => (ConstBool [c != d])
  2321  (EqPtr  (Convert (Addr {x} _) _) (Addr {y} _)) => (ConstBool [x==y])
  2322  (NeqPtr (Convert (Addr {x} _) _) (Addr {y} _)) => (ConstBool [x!=y])
  2323  
  2324  (EqPtr  (LocalAddr _ _) (Addr _)) => (ConstBool [false])
  2325  (EqPtr  (OffPtr (LocalAddr _ _)) (Addr _)) => (ConstBool [false])
  2326  (EqPtr  (LocalAddr _ _) (OffPtr (Addr _))) => (ConstBool [false])
  2327  (EqPtr  (OffPtr (LocalAddr _ _)) (OffPtr (Addr _))) => (ConstBool [false])
  2328  (NeqPtr (LocalAddr _ _) (Addr _)) => (ConstBool [true])
  2329  (NeqPtr (OffPtr (LocalAddr _ _)) (Addr _)) => (ConstBool [true])
  2330  (NeqPtr (LocalAddr _ _) (OffPtr (Addr _))) => (ConstBool [true])
  2331  (NeqPtr (OffPtr (LocalAddr _ _)) (OffPtr (Addr _))) => (ConstBool [true])
  2332  
  2333  // Simplify address comparisons.
  2334  (EqPtr  (AddPtr p1 o1) p2) && isSamePtr(p1, p2) => (Not (IsNonNil o1))
  2335  (NeqPtr (AddPtr p1 o1) p2) && isSamePtr(p1, p2) => (IsNonNil o1)
  2336  (EqPtr  (Const(32|64) [0]) p) => (Not (IsNonNil p))
  2337  (NeqPtr (Const(32|64) [0]) p) => (IsNonNil p)
  2338  (EqPtr  (ConstNil) p) => (Not (IsNonNil p))
  2339  (NeqPtr (ConstNil) p) => (IsNonNil p)
  2340  
  2341  // Evaluate constant user nil checks.
  2342  (IsNonNil (ConstNil)) => (ConstBool [false])
  2343  (IsNonNil (Const(32|64) [c])) => (ConstBool [c != 0])
  2344  (IsNonNil          (Addr _)   ) => (ConstBool [true])
  2345  (IsNonNil (Convert (Addr _) _)) => (ConstBool [true])
  2346  (IsNonNil (LocalAddr _ _)) => (ConstBool [true])
  2347  
  2348  // Inline small or disjoint runtime.memmove calls with constant length.
  2349  // See the comment in op Move in genericOps.go for discussion of the type.
  2350  //
  2351  // Note that we've lost any knowledge of the type and alignment requirements
  2352  // of the source and destination. We only know the size, and that the type
  2353  // contains no pointers.
  2354  // The type of the move is not necessarily v.Args[0].Type().Elem()!
  2355  // See issue 55122 for details.
  2356  //
  2357  // Because expand calls runs after prove, constants useful to this pattern may not appear.
  2358  // Both versions need to exist; the memory and register variants.
  2359  //
  2360  // Match post-expansion calls, memory version.
  2361  (SelectN [0] call:(StaticCall {sym} s1:(Store _ (Const(64|32) [sz]) s2:(Store  _ src s3:(Store {t} _ dst mem)))))
  2362  	&& sz >= 0
  2363  	&& isSameCall(sym, "runtime.memmove")
  2364  	&& s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1
  2365  	&& isInlinableMemmove(dst, src, int64(sz), config)
  2366  	&& clobber(s1, s2, s3, call)
  2367  	=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
  2368  
  2369  // Match post-expansion calls, register version.
  2370  (SelectN [0] call:(StaticCall {sym} dst src (Const(64|32) [sz]) mem))
  2371  	&& sz >= 0
  2372  	&& call.Uses == 1 // this will exclude all calls with results
  2373  	&& isSameCall(sym, "runtime.memmove")
  2374  	&& isInlinableMemmove(dst, src, int64(sz), config)
  2375  	&& clobber(call)
  2376  	=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
  2377  
  2378  // Match pre-expansion calls.
  2379  (SelectN [0] call:(StaticLECall {sym} dst src (Const(64|32) [sz]) mem))
  2380  	&& sz >= 0
  2381  	&& call.Uses == 1 // this will exclude all calls with results
  2382  	&& isSameCall(sym, "runtime.memmove")
  2383  	&& isInlinableMemmove(dst, src, int64(sz), config)
  2384  	&& clobber(call)
  2385  	=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
  2386  
  2387  // De-virtualize late-expanded interface calls into late-expanded static calls.
  2388  (InterLECall [argsize] {auxCall} (Addr {fn} (SB)) ___) => devirtLECall(v, fn.(*obj.LSym))
  2389  
  2390  // Move and Zero optimizations.
  2391  // Move source and destination may overlap.
  2392  
  2393  // Convert Moves into Zeros when the source is known to be zeros.
  2394  (Move {t} [n] dst1 src mem:(Zero {t} [n] dst2 _)) && isSamePtr(src, dst2)
  2395  	=> (Zero {t} [n] dst1 mem)
  2396  (Move {t} [n] dst1 src mem:(VarDef (Zero {t} [n] dst0 _))) && isSamePtr(src, dst0)
  2397  	=> (Zero {t} [n] dst1 mem)
  2398  (Move {t} [n] dst (Addr {sym} (SB)) mem) && symIsROZero(sym) => (Zero {t} [n] dst mem)
  2399  
  2400  // Don't Store to variables that are about to be overwritten by Move/Zero.
  2401  (Zero {t1} [n] p1 store:(Store {t2} (OffPtr [o2] p2) _ mem))
  2402  	&& isSamePtr(p1, p2) && store.Uses == 1
  2403  	&& n >= o2 + t2.Size()
  2404  	&& clobber(store)
  2405  	=> (Zero {t1} [n] p1 mem)
  2406  (Move {t1} [n] dst1 src1 store:(Store {t2} op:(OffPtr [o2] dst2) _ mem))
  2407  	&& isSamePtr(dst1, dst2) && store.Uses == 1
  2408  	&& n >= o2 + t2.Size()
  2409  	&& disjoint(src1, n, op, t2.Size())
  2410  	&& clobber(store)
  2411  	=> (Move {t1} [n] dst1 src1 mem)
  2412  
  2413  // Don't Move to variables that are immediately completely overwritten.
  2414  (Zero {t} [n] dst1 move:(Move {t} [n] dst2 _ mem))
  2415  	&& move.Uses == 1
  2416  	&& isSamePtr(dst1, dst2)
  2417  	&& clobber(move)
  2418  	=> (Zero {t} [n] dst1 mem)
  2419  (Move {t} [n] dst1 src1 move:(Move {t} [n] dst2 _ mem))
  2420  	&& move.Uses == 1
  2421  	&& isSamePtr(dst1, dst2) && disjoint(src1, n, dst2, n)
  2422  	&& clobber(move)
  2423  	=> (Move {t} [n] dst1 src1 mem)
  2424  (Zero {t} [n] dst1 vardef:(VarDef {x} move:(Move {t} [n] dst2 _ mem)))
  2425  	&& move.Uses == 1 && vardef.Uses == 1
  2426  	&& isSamePtr(dst1, dst2)
  2427  	&& clobber(move, vardef)
  2428  	=> (Zero {t} [n] dst1 (VarDef {x} mem))
  2429  (Move {t} [n] dst1 src1 vardef:(VarDef {x} move:(Move {t} [n] dst2 _ mem)))
  2430  	&& move.Uses == 1 && vardef.Uses == 1
  2431  	&& isSamePtr(dst1, dst2) && disjoint(src1, n, dst2, n)
  2432  	&& clobber(move, vardef)
  2433  	=> (Move {t} [n] dst1 src1 (VarDef {x} mem))
  2434  (Store {t1} op1:(OffPtr [o1] p1) d1
  2435  	m2:(Store {t2} op2:(OffPtr [0] p2) d2
  2436  		m3:(Move [n] p3 _ mem)))
  2437  	&& m2.Uses == 1 && m3.Uses == 1
  2438  	&& o1 == t2.Size()
  2439  	&& n == t2.Size() + t1.Size()
  2440  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2441  	&& clobber(m2, m3)
  2442  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 mem))
  2443  (Store {t1} op1:(OffPtr [o1] p1) d1
  2444  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  2445  		m3:(Store {t3} op3:(OffPtr [0] p3) d3
  2446  			m4:(Move [n] p4 _ mem))))
  2447  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1
  2448  	&& o2 == t3.Size()
  2449  	&& o1-o2 == t2.Size()
  2450  	&& n == t3.Size() + t2.Size() + t1.Size()
  2451  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2452  	&& clobber(m2, m3, m4)
  2453  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 mem)))
  2454  (Store {t1} op1:(OffPtr [o1] p1) d1
  2455  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  2456  		m3:(Store {t3} op3:(OffPtr [o3] p3) d3
  2457  			m4:(Store {t4} op4:(OffPtr [0] p4) d4
  2458  				m5:(Move [n] p5 _ mem)))))
  2459  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1 && m5.Uses == 1
  2460  	&& o3 == t4.Size()
  2461  	&& o2-o3 == t3.Size()
  2462  	&& o1-o2 == t2.Size()
  2463  	&& n == t4.Size() + t3.Size() + t2.Size() + t1.Size()
  2464  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2465  	&& clobber(m2, m3, m4, m5)
  2466  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 (Store {t4} op4 d4 mem))))
  2467  
  2468  // Don't Zero variables that are immediately completely overwritten
  2469  // before being accessed.
  2470  (Move {t} [n] dst1 src1 zero:(Zero {t} [n] dst2 mem))
  2471  	&& zero.Uses == 1
  2472  	&& isSamePtr(dst1, dst2) && disjoint(src1, n, dst2, n)
  2473  	&& clobber(zero)
  2474  	=> (Move {t} [n] dst1 src1 mem)
  2475  (Move {t} [n] dst1 src1 vardef:(VarDef {x} zero:(Zero {t} [n] dst2 mem)))
  2476  	&& zero.Uses == 1 && vardef.Uses == 1
  2477  	&& isSamePtr(dst1, dst2) && disjoint(src1, n, dst2, n)
  2478  	&& clobber(zero, vardef)
  2479  	=> (Move {t} [n] dst1 src1 (VarDef {x} mem))
  2480  (Store {t1} op1:(OffPtr [o1] p1) d1
  2481  	m2:(Store {t2} op2:(OffPtr [0] p2) d2
  2482  		m3:(Zero [n] p3 mem)))
  2483  	&& m2.Uses == 1 && m3.Uses == 1
  2484  	&& o1 == t2.Size()
  2485  	&& n == t2.Size() + t1.Size()
  2486  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2487  	&& clobber(m2, m3)
  2488  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 mem))
  2489  (Store {t1} op1:(OffPtr [o1] p1) d1
  2490  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  2491  		m3:(Store {t3} op3:(OffPtr [0] p3) d3
  2492  			m4:(Zero [n] p4 mem))))
  2493  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1
  2494  	&& o2 == t3.Size()
  2495  	&& o1-o2 == t2.Size()
  2496  	&& n == t3.Size() + t2.Size() + t1.Size()
  2497  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2498  	&& clobber(m2, m3, m4)
  2499  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 mem)))
  2500  (Store {t1} op1:(OffPtr [o1] p1) d1
  2501  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  2502  		m3:(Store {t3} op3:(OffPtr [o3] p3) d3
  2503  			m4:(Store {t4} op4:(OffPtr [0] p4) d4
  2504  				m5:(Zero [n] p5 mem)))))
  2505  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1 && m5.Uses == 1
  2506  	&& o3 == t4.Size()
  2507  	&& o2-o3 == t3.Size()
  2508  	&& o1-o2 == t2.Size()
  2509  	&& n == t4.Size() + t3.Size() + t2.Size() + t1.Size()
  2510  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2511  	&& clobber(m2, m3, m4, m5)
  2512  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 (Store {t4} op4 d4 mem))))
  2513  
  2514  // Don't Move from memory if the values are likely to already be
  2515  // in registers.
  2516  (Move {t1} [n] dst p1
  2517  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2518  		(Store {t3} op3:(OffPtr <tt3> [0] p3) d2 _)))
  2519  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2520  	&& t2.Alignment() <= t1.Alignment()
  2521  	&& t3.Alignment() <= t1.Alignment()
  2522  	&& registerizable(b, t2)
  2523  	&& registerizable(b, t3)
  2524  	&& o2 == t3.Size()
  2525  	&& n == t2.Size() + t3.Size()
  2526  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2527  		(Store {t3} (OffPtr <tt3> [0] dst) d2 mem))
  2528  (Move {t1} [n] dst p1
  2529  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2530  		(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  2531  			(Store {t4} op4:(OffPtr <tt4> [0] p4) d3 _))))
  2532  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2533  	&& t2.Alignment() <= t1.Alignment()
  2534  	&& t3.Alignment() <= t1.Alignment()
  2535  	&& t4.Alignment() <= t1.Alignment()
  2536  	&& registerizable(b, t2)
  2537  	&& registerizable(b, t3)
  2538  	&& registerizable(b, t4)
  2539  	&& o3 == t4.Size()
  2540  	&& o2-o3 == t3.Size()
  2541  	&& n == t2.Size() + t3.Size() + t4.Size()
  2542  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2543  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2544  			(Store {t4} (OffPtr <tt4> [0] dst) d3 mem)))
  2545  (Move {t1} [n] dst p1
  2546  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2547  		(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  2548  			(Store {t4} op4:(OffPtr <tt4> [o4] p4) d3
  2549  				(Store {t5} op5:(OffPtr <tt5> [0] p5) d4 _)))))
  2550  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2551  	&& t2.Alignment() <= t1.Alignment()
  2552  	&& t3.Alignment() <= t1.Alignment()
  2553  	&& t4.Alignment() <= t1.Alignment()
  2554  	&& t5.Alignment() <= t1.Alignment()
  2555  	&& registerizable(b, t2)
  2556  	&& registerizable(b, t3)
  2557  	&& registerizable(b, t4)
  2558  	&& registerizable(b, t5)
  2559  	&& o4 == t5.Size()
  2560  	&& o3-o4 == t4.Size()
  2561  	&& o2-o3 == t3.Size()
  2562  	&& n == t2.Size() + t3.Size() + t4.Size() + t5.Size()
  2563  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2564  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2565  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2566  				(Store {t5} (OffPtr <tt5> [0] dst) d4 mem))))
  2567  
  2568  // Same thing but with VarDef in the middle.
  2569  (Move {t1} [n] dst p1
  2570  	mem:(VarDef
  2571  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2572  			(Store {t3} op3:(OffPtr <tt3> [0] p3) d2 _))))
  2573  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2574  	&& t2.Alignment() <= t1.Alignment()
  2575  	&& t3.Alignment() <= t1.Alignment()
  2576  	&& registerizable(b, t2)
  2577  	&& registerizable(b, t3)
  2578  	&& o2 == t3.Size()
  2579  	&& n == t2.Size() + t3.Size()
  2580  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2581  		(Store {t3} (OffPtr <tt3> [0] dst) d2 mem))
  2582  (Move {t1} [n] dst p1
  2583  	mem:(VarDef
  2584  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2585  			(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  2586  				(Store {t4} op4:(OffPtr <tt4> [0] p4) d3 _)))))
  2587  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2588  	&& t2.Alignment() <= t1.Alignment()
  2589  	&& t3.Alignment() <= t1.Alignment()
  2590  	&& t4.Alignment() <= t1.Alignment()
  2591  	&& registerizable(b, t2)
  2592  	&& registerizable(b, t3)
  2593  	&& registerizable(b, t4)
  2594  	&& o3 == t4.Size()
  2595  	&& o2-o3 == t3.Size()
  2596  	&& n == t2.Size() + t3.Size() + t4.Size()
  2597  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2598  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2599  			(Store {t4} (OffPtr <tt4> [0] dst) d3 mem)))
  2600  (Move {t1} [n] dst p1
  2601  	mem:(VarDef
  2602  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2603  			(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  2604  				(Store {t4} op4:(OffPtr <tt4> [o4] p4) d3
  2605  					(Store {t5} op5:(OffPtr <tt5> [0] p5) d4 _))))))
  2606  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2607  	&& t2.Alignment() <= t1.Alignment()
  2608  	&& t3.Alignment() <= t1.Alignment()
  2609  	&& t4.Alignment() <= t1.Alignment()
  2610  	&& t5.Alignment() <= t1.Alignment()
  2611  	&& registerizable(b, t2)
  2612  	&& registerizable(b, t3)
  2613  	&& registerizable(b, t4)
  2614  	&& registerizable(b, t5)
  2615  	&& o4 == t5.Size()
  2616  	&& o3-o4 == t4.Size()
  2617  	&& o2-o3 == t3.Size()
  2618  	&& n == t2.Size() + t3.Size() + t4.Size() + t5.Size()
  2619  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2620  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2621  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2622  				(Store {t5} (OffPtr <tt5> [0] dst) d4 mem))))
  2623  
  2624  // Prefer to Zero and Store than to Move.
  2625  (Move {t1} [n] dst p1
  2626  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2627  		(Zero {t3} [n] p3 _)))
  2628  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2629  	&& t2.Alignment() <= t1.Alignment()
  2630  	&& t3.Alignment() <= t1.Alignment()
  2631  	&& registerizable(b, t2)
  2632  	&& n >= o2 + t2.Size()
  2633  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2634  		(Zero {t1} [n] dst mem))
  2635  (Move {t1} [n] dst p1
  2636  	mem:(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2637  		(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2638  			(Zero {t4} [n] p4 _))))
  2639  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2640  	&& t2.Alignment() <= t1.Alignment()
  2641  	&& t3.Alignment() <= t1.Alignment()
  2642  	&& t4.Alignment() <= t1.Alignment()
  2643  	&& registerizable(b, t2)
  2644  	&& registerizable(b, t3)
  2645  	&& n >= o2 + t2.Size()
  2646  	&& n >= o3 + t3.Size()
  2647  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2648  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2649  			(Zero {t1} [n] dst mem)))
  2650  (Move {t1} [n] dst p1
  2651  	mem:(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2652  		(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2653  			(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2654  				(Zero {t5} [n] p5 _)))))
  2655  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2656  	&& t2.Alignment() <= t1.Alignment()
  2657  	&& t3.Alignment() <= t1.Alignment()
  2658  	&& t4.Alignment() <= t1.Alignment()
  2659  	&& t5.Alignment() <= t1.Alignment()
  2660  	&& registerizable(b, t2)
  2661  	&& registerizable(b, t3)
  2662  	&& registerizable(b, t4)
  2663  	&& n >= o2 + t2.Size()
  2664  	&& n >= o3 + t3.Size()
  2665  	&& n >= o4 + t4.Size()
  2666  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2667  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2668  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2669  				(Zero {t1} [n] dst mem))))
  2670  (Move {t1} [n] dst p1
  2671  	mem:(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2672  		(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2673  			(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2674  				(Store {t5} (OffPtr <tt5> [o5] p5) d4
  2675  					(Zero {t6} [n] p6 _))))))
  2676  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5) && isSamePtr(p5, p6)
  2677  	&& t2.Alignment() <= t1.Alignment()
  2678  	&& t3.Alignment() <= t1.Alignment()
  2679  	&& t4.Alignment() <= t1.Alignment()
  2680  	&& t5.Alignment() <= t1.Alignment()
  2681  	&& t6.Alignment() <= t1.Alignment()
  2682  	&& registerizable(b, t2)
  2683  	&& registerizable(b, t3)
  2684  	&& registerizable(b, t4)
  2685  	&& registerizable(b, t5)
  2686  	&& n >= o2 + t2.Size()
  2687  	&& n >= o3 + t3.Size()
  2688  	&& n >= o4 + t4.Size()
  2689  	&& n >= o5 + t5.Size()
  2690  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2691  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2692  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2693  				(Store {t5} (OffPtr <tt5> [o5] dst) d4
  2694  					(Zero {t1} [n] dst mem)))))
  2695  (Move {t1} [n] dst p1
  2696  	mem:(VarDef
  2697  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2698  			(Zero {t3} [n] p3 _))))
  2699  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2700  	&& t2.Alignment() <= t1.Alignment()
  2701  	&& t3.Alignment() <= t1.Alignment()
  2702  	&& registerizable(b, t2)
  2703  	&& n >= o2 + t2.Size()
  2704  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2705  		(Zero {t1} [n] dst mem))
  2706  (Move {t1} [n] dst p1
  2707  	mem:(VarDef
  2708  		(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2709  			(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2710  				(Zero {t4} [n] p4 _)))))
  2711  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2712  	&& t2.Alignment() <= t1.Alignment()
  2713  	&& t3.Alignment() <= t1.Alignment()
  2714  	&& t4.Alignment() <= t1.Alignment()
  2715  	&& registerizable(b, t2)
  2716  	&& registerizable(b, t3)
  2717  	&& n >= o2 + t2.Size()
  2718  	&& n >= o3 + t3.Size()
  2719  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2720  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2721  			(Zero {t1} [n] dst mem)))
  2722  (Move {t1} [n] dst p1
  2723  	mem:(VarDef
  2724  		(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2725  			(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2726  				(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2727  					(Zero {t5} [n] p5 _))))))
  2728  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2729  	&& t2.Alignment() <= t1.Alignment()
  2730  	&& t3.Alignment() <= t1.Alignment()
  2731  	&& t4.Alignment() <= t1.Alignment()
  2732  	&& t5.Alignment() <= t1.Alignment()
  2733  	&& registerizable(b, t2)
  2734  	&& registerizable(b, t3)
  2735  	&& registerizable(b, t4)
  2736  	&& n >= o2 + t2.Size()
  2737  	&& n >= o3 + t3.Size()
  2738  	&& n >= o4 + t4.Size()
  2739  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2740  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2741  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2742  				(Zero {t1} [n] dst mem))))
  2743  (Move {t1} [n] dst p1
  2744  	mem:(VarDef
  2745  		(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2746  			(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2747  				(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2748  					(Store {t5} (OffPtr <tt5> [o5] p5) d4
  2749  						(Zero {t6} [n] p6 _)))))))
  2750  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5) && isSamePtr(p5, p6)
  2751  	&& t2.Alignment() <= t1.Alignment()
  2752  	&& t3.Alignment() <= t1.Alignment()
  2753  	&& t4.Alignment() <= t1.Alignment()
  2754  	&& t5.Alignment() <= t1.Alignment()
  2755  	&& t6.Alignment() <= t1.Alignment()
  2756  	&& registerizable(b, t2)
  2757  	&& registerizable(b, t3)
  2758  	&& registerizable(b, t4)
  2759  	&& registerizable(b, t5)
  2760  	&& n >= o2 + t2.Size()
  2761  	&& n >= o3 + t3.Size()
  2762  	&& n >= o4 + t4.Size()
  2763  	&& n >= o5 + t5.Size()
  2764  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2765  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2766  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2767  				(Store {t5} (OffPtr <tt5> [o5] dst) d4
  2768  					(Zero {t1} [n] dst mem)))))
  2769  
  2770  (SelectN [0] call:(StaticLECall {sym} a x)) && needRaceCleanup(sym, call) && clobber(call) => x
  2771  (SelectN [0] call:(StaticLECall {sym} x)) && needRaceCleanup(sym, call) && clobber(call) => x
  2772  
  2773  // When rewriting append to growslice, we use as the new length the result of
  2774  // growslice so that we don't have to spill/restore the new length around the growslice call.
  2775  // The exception here is that if the new length is a constant, avoiding spilling it
  2776  // is pointless and its constantness is sometimes useful for subsequent optimizations.
  2777  // See issue 56440.
  2778  // Note there are 2 rules here, one for the pre-decomposed []T result and one for
  2779  // the post-decomposed (*T,int,int) result. (The latter is generated after call expansion.)
  2780  (SliceLen (SelectN [0] (StaticLECall {sym} _ newLen:(Const(64|32)) _ _ _ _))) && isSameCall(sym, "runtime.growslice") => newLen
  2781  (SelectN [1] (StaticCall {sym} _ newLen:(Const(64|32)) _ _ _ _)) && v.Type.IsInteger() && isSameCall(sym, "runtime.growslice") => newLen
  2782  
  2783  // Collapse moving A -> B -> C into just A -> C.
  2784  // Later passes (deadstore, elim unread auto) will remove the A -> B move, if possible.
  2785  // This happens most commonly when B is an autotmp inserted earlier
  2786  // during compilation to ensure correctness.
  2787  // Take care that overlapping moves are preserved.
  2788  // Restrict this optimization to the stack, to avoid duplicating loads from the heap;
  2789  // see CL 145208 for discussion.
  2790  (Move {t1} [s] dst tmp1 midmem:(Move {t2} [s] tmp2 src _))
  2791  	&& t1.Compare(t2) == types.CMPeq
  2792  	&& isSamePtr(tmp1, tmp2)
  2793  	&& isStackPtr(src) && !isVolatile(src)
  2794  	&& disjoint(src, s, tmp2, s)
  2795  	&& (disjoint(src, s, dst, s) || isInlinableMemmove(dst, src, s, config))
  2796  	=> (Move {t1} [s] dst src midmem)
  2797  
  2798  // Same, but for large types that require VarDefs.
  2799  (Move {t1} [s] dst tmp1 midmem:(VarDef (Move {t2} [s] tmp2 src _)))
  2800  	&& t1.Compare(t2) == types.CMPeq
  2801  	&& isSamePtr(tmp1, tmp2)
  2802  	&& isStackPtr(src) && !isVolatile(src)
  2803  	&& disjoint(src, s, tmp2, s)
  2804  	&& (disjoint(src, s, dst, s) || isInlinableMemmove(dst, src, s, config))
  2805  	=> (Move {t1} [s] dst src midmem)
  2806  
  2807  // Don't zero the same bits twice.
  2808  (Zero {t} [s] dst1 zero:(Zero {t} [s] dst2 _)) && isSamePtr(dst1, dst2) => zero
  2809  (Zero {t} [s] dst1 vardef:(VarDef (Zero {t} [s] dst2 _))) && isSamePtr(dst1, dst2) => vardef
  2810  
  2811  // Elide self-moves. This only happens rarely (e.g test/fixedbugs/bug277.go).
  2812  // However, this rule is needed to prevent the previous rule from looping forever in such cases.
  2813  (Move dst src mem) && isSamePtr(dst, src) => mem
  2814  
  2815  // Constant rotate detection.
  2816  ((Add64|Or64|Xor64) (Lsh64x64 x z:(Const64 <t> [c])) (Rsh64Ux64 x (Const64 [d]))) && c < 64 && d == 64-c && canRotate(config, 64) => (RotateLeft64 x z)
  2817  ((Add32|Or32|Xor32) (Lsh32x64 x z:(Const64 <t> [c])) (Rsh32Ux64 x (Const64 [d]))) && c < 32 && d == 32-c && canRotate(config, 32) => (RotateLeft32 x z)
  2818  ((Add16|Or16|Xor16) (Lsh16x64 x z:(Const64 <t> [c])) (Rsh16Ux64 x (Const64 [d]))) && c < 16 && d == 16-c && canRotate(config, 16) => (RotateLeft16 x z)
  2819  ((Add8|Or8|Xor8) (Lsh8x64 x z:(Const64 <t> [c])) (Rsh8Ux64 x (Const64 [d]))) && c < 8 && d == 8-c && canRotate(config, 8) => (RotateLeft8 x z)
  2820  
  2821  // Non-constant rotate detection.
  2822  // We use shiftIsBounded to make sure that neither of the shifts are >64.
  2823  // Note: these rules are subtle when the shift amounts are 0/64, as Go shifts
  2824  // are different from most native shifts. But it works out.
  2825  ((Add64|Or64|Xor64) left:(Lsh64x64 x y) right:(Rsh64Ux64 x (Sub64 (Const64 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2826  ((Add64|Or64|Xor64) left:(Lsh64x32 x y) right:(Rsh64Ux32 x (Sub32 (Const32 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2827  ((Add64|Or64|Xor64) left:(Lsh64x16 x y) right:(Rsh64Ux16 x (Sub16 (Const16 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2828  ((Add64|Or64|Xor64) left:(Lsh64x8  x y) right:(Rsh64Ux8  x (Sub8  (Const8  [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2829  
  2830  ((Add64|Or64|Xor64) right:(Rsh64Ux64 x y) left:(Lsh64x64 x z:(Sub64 (Const64 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2831  ((Add64|Or64|Xor64) right:(Rsh64Ux32 x y) left:(Lsh64x32 x z:(Sub32 (Const32 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2832  ((Add64|Or64|Xor64) right:(Rsh64Ux16 x y) left:(Lsh64x16 x z:(Sub16 (Const16 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2833  ((Add64|Or64|Xor64) right:(Rsh64Ux8  x y) left:(Lsh64x8  x z:(Sub8  (Const8  [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2834  
  2835  ((Add32|Or32|Xor32) left:(Lsh32x64 x y) right:(Rsh32Ux64 x (Sub64 (Const64 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2836  ((Add32|Or32|Xor32) left:(Lsh32x32 x y) right:(Rsh32Ux32 x (Sub32 (Const32 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2837  ((Add32|Or32|Xor32) left:(Lsh32x16 x y) right:(Rsh32Ux16 x (Sub16 (Const16 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2838  ((Add32|Or32|Xor32) left:(Lsh32x8  x y) right:(Rsh32Ux8  x (Sub8  (Const8  [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2839  
  2840  ((Add32|Or32|Xor32) right:(Rsh32Ux64 x y) left:(Lsh32x64 x z:(Sub64 (Const64 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2841  ((Add32|Or32|Xor32) right:(Rsh32Ux32 x y) left:(Lsh32x32 x z:(Sub32 (Const32 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2842  ((Add32|Or32|Xor32) right:(Rsh32Ux16 x y) left:(Lsh32x16 x z:(Sub16 (Const16 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2843  ((Add32|Or32|Xor32) right:(Rsh32Ux8  x y) left:(Lsh32x8  x z:(Sub8  (Const8  [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2844  
  2845  ((Add16|Or16|Xor16) left:(Lsh16x64 x y) right:(Rsh16Ux64 x (Sub64 (Const64 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2846  ((Add16|Or16|Xor16) left:(Lsh16x32 x y) right:(Rsh16Ux32 x (Sub32 (Const32 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2847  ((Add16|Or16|Xor16) left:(Lsh16x16 x y) right:(Rsh16Ux16 x (Sub16 (Const16 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2848  ((Add16|Or16|Xor16) left:(Lsh16x8  x y) right:(Rsh16Ux8  x (Sub8  (Const8  [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2849  
  2850  ((Add16|Or16|Xor16) right:(Rsh16Ux64 x y) left:(Lsh16x64 x z:(Sub64 (Const64 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2851  ((Add16|Or16|Xor16) right:(Rsh16Ux32 x y) left:(Lsh16x32 x z:(Sub32 (Const32 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2852  ((Add16|Or16|Xor16) right:(Rsh16Ux16 x y) left:(Lsh16x16 x z:(Sub16 (Const16 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2853  ((Add16|Or16|Xor16) right:(Rsh16Ux8  x y) left:(Lsh16x8  x z:(Sub8  (Const8  [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2854  
  2855  ((Add8|Or8|Xor8) left:(Lsh8x64 x y) right:(Rsh8Ux64 x (Sub64 (Const64 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2856  ((Add8|Or8|Xor8) left:(Lsh8x32 x y) right:(Rsh8Ux32 x (Sub32 (Const32 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2857  ((Add8|Or8|Xor8) left:(Lsh8x16 x y) right:(Rsh8Ux16 x (Sub16 (Const16 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2858  ((Add8|Or8|Xor8) left:(Lsh8x8  x y) right:(Rsh8Ux8  x (Sub8  (Const8  [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2859  
  2860  ((Add8|Or8|Xor8) right:(Rsh8Ux64 x y) left:(Lsh8x64 x z:(Sub64 (Const64 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2861  ((Add8|Or8|Xor8) right:(Rsh8Ux32 x y) left:(Lsh8x32 x z:(Sub32 (Const32 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2862  ((Add8|Or8|Xor8) right:(Rsh8Ux16 x y) left:(Lsh8x16 x z:(Sub16 (Const16 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2863  ((Add8|Or8|Xor8) right:(Rsh8Ux8  x y) left:(Lsh8x8  x z:(Sub8  (Const8  [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2864  
  2865  // Rotating by y&c, with c a mask that doesn't change the bottom bits, is the same as rotating by y.
  2866  (RotateLeft64 x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&63 == 63 => (RotateLeft64 x y)
  2867  (RotateLeft32 x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&31 == 31 => (RotateLeft32 x y)
  2868  (RotateLeft16 x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&15 == 15 => (RotateLeft16 x y)
  2869  (RotateLeft8  x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&7  == 7  => (RotateLeft8  x y)
  2870  
  2871  // Rotating by -(y&c), with c a mask that doesn't change the bottom bits, is the same as rotating by -y.
  2872  (RotateLeft64 x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&63 == 63 => (RotateLeft64 x (Neg(64|32|16|8) <y.Type> y))
  2873  (RotateLeft32 x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&31 == 31 => (RotateLeft32 x (Neg(64|32|16|8) <y.Type> y))
  2874  (RotateLeft16 x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&15 == 15 => (RotateLeft16 x (Neg(64|32|16|8) <y.Type> y))
  2875  (RotateLeft8  x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&7  == 7  => (RotateLeft8  x (Neg(64|32|16|8) <y.Type> y))
  2876  
  2877  // Rotating by y+c, with c a multiple of the value width, is the same as rotating by y.
  2878  (RotateLeft64 x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&63 == 0 => (RotateLeft64 x y)
  2879  (RotateLeft32 x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&31 == 0 => (RotateLeft32 x y)
  2880  (RotateLeft16 x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&15 == 0 => (RotateLeft16 x y)
  2881  (RotateLeft8  x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&7  == 0 => (RotateLeft8  x y)
  2882  
  2883  // Rotating by c-y, with c a multiple of the value width, is the same as rotating by -y.
  2884  (RotateLeft64 x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&63 == 0 => (RotateLeft64 x (Neg(64|32|16|8) <y.Type> y))
  2885  (RotateLeft32 x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&31 == 0 => (RotateLeft32 x (Neg(64|32|16|8) <y.Type> y))
  2886  (RotateLeft16 x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&15 == 0 => (RotateLeft16 x (Neg(64|32|16|8) <y.Type> y))
  2887  (RotateLeft8  x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&7  == 0 => (RotateLeft8  x (Neg(64|32|16|8) <y.Type> y))
  2888  
  2889  // Ensure we don't do Const64 rotates in a 32-bit system.
  2890  (RotateLeft64 x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft64 x (Const32 <t> [int32(c)]))
  2891  (RotateLeft32 x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft32 x (Const32 <t> [int32(c)]))
  2892  (RotateLeft16 x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft16 x (Const32 <t> [int32(c)]))
  2893  (RotateLeft8  x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft8  x (Const32 <t> [int32(c)]))
  2894  
  2895  // Rotating by c, then by d, is the same as rotating by c+d.
  2896  // We're trading a rotate for an add, which seems generally a good choice. It is especially good when c and d are constants.
  2897  // This rule is a bit tricky as c and d might be different widths. We handle only cases where they are the same width.
  2898  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 8 && d.Type.Size() == 8 => (RotateLeft(64|32|16|8) x (Add64 <c.Type> c d))
  2899  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 4 && d.Type.Size() == 4 => (RotateLeft(64|32|16|8) x (Add32 <c.Type> c d))
  2900  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 2 && d.Type.Size() == 2 => (RotateLeft(64|32|16|8) x (Add16 <c.Type> c d))
  2901  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 1 && d.Type.Size() == 1 => (RotateLeft(64|32|16|8) x (Add8  <c.Type> c d))
  2902  
  2903  // Loading fixed addresses and constants.
  2904  (Load                                     (Addr {s} sb)         _)  && isFixedLoad(v, s,   0) => rewriteFixedLoad(v, s, sb,   0)
  2905  (Load                            (Convert (Addr {s} sb) _)      _)  && isFixedLoad(v, s,   0) => rewriteFixedLoad(v, s, sb,   0)
  2906  (Load               (ITab (IMake          (Addr {s} sb)    _))  _)  && isFixedLoad(v, s,   0) => rewriteFixedLoad(v, s, sb,   0)
  2907  (Load               (ITab (IMake (Convert (Addr {s} sb) _) _))  _)  && isFixedLoad(v, s,   0) => rewriteFixedLoad(v, s, sb,   0)
  2908  (Load (OffPtr [off]                       (Addr {s} sb)       ) _)  && isFixedLoad(v, s, off) => rewriteFixedLoad(v, s, sb, off)
  2909  (Load (OffPtr [off]              (Convert (Addr {s} sb) _)    ) _)  && isFixedLoad(v, s, off) => rewriteFixedLoad(v, s, sb, off)
  2910  (Load (OffPtr [off] (ITab (IMake          (Addr {s} sb)    _))) _)  && isFixedLoad(v, s, off) => rewriteFixedLoad(v, s, sb, off)
  2911  (Load (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _)  && isFixedLoad(v, s, off) => rewriteFixedLoad(v, s, sb, off)
  2912  
  2913  // Calling cmpstring a second time with the same arguments in the
  2914  // same memory state can reuse the results of the first call.
  2915  // See issue 61725.
  2916  // Note that this could pretty easily generalize to any pure function.
  2917  (SelectN [0] (StaticLECall {f} x y (SelectN [1] c:(StaticLECall {g} x y mem))))
  2918    && isSameCall(f, "runtime.cmpstring")
  2919    && isSameCall(g, "runtime.cmpstring")
  2920  => @c.Block (SelectN [0] <typ.Int> c)
  2921  
  2922  // If we don't use the result of cmpstring, might as well not call it.
  2923  // Note that this could pretty easily generalize to any pure function.
  2924  (SelectN [1] c:(StaticLECall {f} _ _ mem)) && c.Uses == 1 && isSameCall(f, "runtime.cmpstring") && clobber(c) => mem
  2925  
  2926  // We can easily compute the result of efaceeq if
  2927  // we know the underlying type is pointer-ish.
  2928  (StaticLECall {f} typ_ x y mem)
  2929  	&& isSameCall(f, "runtime.efaceeq")
  2930  	&& isDirectType(typ_)
  2931  	&& clobber(v)
  2932  	=> (MakeResult (EqPtr x y) mem)
  2933  
  2934  // We can easily compute the result of ifaceeq if
  2935  // we know the underlying type is pointer-ish.
  2936  (StaticLECall {f} itab x y mem)
  2937  	&& isSameCall(f, "runtime.ifaceeq")
  2938  	&& isDirectIface(itab)
  2939  	&& clobber(v)
  2940  	=> (MakeResult (EqPtr x y) mem)
  2941  
  2942  // If we use the result of slicebytetostring in a map lookup operation,
  2943  // then we don't need to actually do the []byte->string conversion.
  2944  // We can just use the ptr/len of the byte slice directly as a (temporary) string.
  2945  //
  2946  // Note that this does not handle some obscure cases like
  2947  // m[[2]string{string(b1), string(b2)}]. There is code in ../walk/order.go
  2948  // which handles some of those cases.
  2949  (StaticLECall {f} [argsize] typ_ map_ key:(SelectN [0] sbts:(StaticLECall {g} _ ptr len mem)) m:(SelectN [1] sbts))
  2950    &&    (isSameCall(f, "runtime.mapaccess1_faststr")
  2951        || isSameCall(f, "runtime.mapaccess2_faststr")
  2952        || isSameCall(f, "runtime.mapdelete_faststr"))
  2953    && isSameCall(g, "runtime.slicebytetostring")
  2954    && key.Uses == 1
  2955    && sbts.Uses == 2
  2956    && resetCopy(m, mem)
  2957    && clobber(sbts)
  2958    && clobber(key)
  2959  => (StaticLECall {f} [argsize] typ_ map_ (StringMake <typ.String> ptr len) mem)
  2960  
  2961  // Similarly to map lookups, also handle unique.Make for strings, which unique.Make will clone.
  2962  (StaticLECall {f} [argsize] dict_ key:(SelectN [0] sbts:(StaticLECall {g} _ ptr len mem)) m:(SelectN [1] sbts))
  2963    && isSameCall(f, "unique.Make[go.shape.string]")
  2964    && isSameCall(g, "runtime.slicebytetostring")
  2965    && key.Uses == 1
  2966    && sbts.Uses == 2
  2967    && resetCopy(m, mem)
  2968    && clobber(sbts)
  2969    && clobber(key)
  2970  => (StaticLECall {f} [argsize] dict_ (StringMake <typ.String> ptr len) mem)
  2971  
  2972  // Transform some CondSelect into math operations.
  2973  // if b { x++ } => x += b // but not on arm64 because it has CSINC
  2974  (CondSelect (Add8 <t> x (Const8 [1])) x bool) && config.arch != "arm64" => (Add8 x (CvtBoolToUint8 <t> bool))
  2975  (CondSelect (Add(64|32|16) <t> x (Const(64|32|16) [1])) x bool) && config.arch != "arm64" => (Add(64|32|16) x (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool)))
  2976  
  2977  // if b { x-- } => x -= b
  2978  (CondSelect (Add8 <t> x (Const8 [-1])) x bool) => (Sub8 x (CvtBoolToUint8 <t> bool))
  2979  (CondSelect (Add(64|32|16) <t> x (Const(64|32|16) [-1])) x bool) => (Sub(64|32|16) x (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool)))
  2980  
  2981  // if b { x <<= 1 } => x <<= b
  2982  (CondSelect (Lsh(64|32|16|8)x64 x (Const64 [1])) x bool) => (Lsh(64|32|16|8)x8 [true] x (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))
  2983  
  2984  // if b { x >>= 1 } => x >>= b
  2985  (CondSelect (Rsh(64|32|16|8)x64 x (Const64 [1])) x bool) => (Rsh(64|32|16|8)x8 [true] x (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))
  2986  (CondSelect (Rsh(64|32|16|8)Ux64 x (Const64 [1])) x bool) => (Rsh(64|32|16|8)Ux8 [true] x (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))
  2987  

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